People Still call D&D's system 'Vancian Magic' though it is far different now than from what it was in the past.
What are your criteria for 'Vacian magic.'  I am not looking for strict sourced definitions, i am looking for what you think off the top of your head.
Sourced definitions can be provided if they are the Basis of your opinion.
No Wrong answers, just seeking opinions. We are not burning at the stake for a different take.

To be honest, it is just phrase people use to describe D&D's magic system to me. Google tells me that it was based on magic system in an old book series, but I had never heard of it.

Same as with Lia I’d never heard of Vance or a Vancian magic system until I was on these forums so to me it’s just a label people apply to the D&D spell slot system 

I first heard the term during the long years of the edition wars. I've always held the opinion that it was the name of a sacred cow that should have made for the holiest of steak dinners.

Greetings GnollItAll78450,

I started playing back in 2nd Edition, all be it briefly, but have been pretty active in 5e, but have never heard this term before.

I said both, since that’s the way it used to work. 
I played starting in becmi, and it was never, to my knowledge, explicitly called that in any official books; it just was that. Based, btw, on the Dying Earth series by Jack Vance. 

The current system isn’t really vancian anymore, imo. In the early editions, if you thought you’d cast a spell more than once in a day, you had to memorize it more than once. So if you had 2 level 1 spell slots, say you memorized magic missile and burning hands. If you cast magic middle, you couldn’t cast it again. The only option left for you was to cast burning hands. If you thought you’d might need 2 magic missiles, you’d memorize that spell twice, and no other spells. 
Also, there was no upcasting, or rituals or cantrips. Casters really had to plan ahead. And clerics pretty much had to memorize heal spells, and only heal spells. Since there was no upcasting, there was just a different, more powerful version of cure wounds with each spell level. Maybe you could sneak a hold person in there eventually  

Personally, while I wouldn’t want to go back to it, I do think it’s one of the changes that contributes to the martial/caster imbalance. The new way really lets casters be more prepared for more situations. 

Quote from Xalthu >>

I said both, since that’s the way it used to work. 
I played starting in becmi, and or was never, to my knowledge, explicitly called that in any official books; it just was that. Based, btw, on the Dying Earth series by Jack Vance. 

The current system isn’t really vancian anymore, imo. In the early editions, if you thought you’d cast a spell more than once in a day, you had to memorize it more than once. So if you had 2 level 1 spell slots, say you memorized magic missile and burning hands. If you cast magic middle, you couldn’t cast it again. The only option left for you was to cast burning hands. If you thought you’d might need 2 magic missiles, you’d memorize that spell twice, and no other spells. 
Also, there was no upcasting, or rituals or cantrips. Casters really had to plan ahead. And clerics pretty much had to memorize heal spells, and only heal spells. Since there was no upcasting, there was just a different, more powerful version of cure wounds with each spell level. Maybe you could sneak a hold person in there eventually  

Personally, while I wouldn’t want to go back to it, I do think it’s one of the changes that contributes to the martial/caster imbalance. The new way really lets casters be more prepared for more situations. 

 Actually, the change has significantly flattened the curve compared to older editions.  Wizards started out as significantly weaker than martials but progressed considerably faster and while they did have to prepare spells, they had enough options that it rarely presented a serious problem unless you tried to seriously overspecialize.

Also, magic item creation was a significantly bigger aspect of previous editions, which meant that casters could make scrolls, potions, and wands to function as ways to extend their powers and improve their versatility.

^^ this.

What we have now is a more flexible hybrid of Vancian magic.  What we had back in 2e (I played older versions first, but 2e is where my memories lie) was a very rigid system.  Could could memorize X number of spells per level, per day, which translates into modern spell slots.  You could cast every spell you memorized, exactly 1 time.  if you wanted to have 2 magic missiles available, you had to memorize it twice.  Ran into a situation where you needed sleep instead of magic missile?  Too bad, you should have planned it out in advance.

What did you do when you were out of spells to cast?  Let me point you to your lord and savior, the dagger.  Because that's what every brave soul I ever saw actually try to play a straight class wizard took.  A big brain play would have probably been the sling, because wizards liked to have better dex scores, and that would make us better at missile combat rather than melee combat which required str.  Your 3 hps (rolled well on that d4) didn't stand up well anyways.  But we were kids, and nobody thought slings were cool, while daggers were at least mini swords.

There was never a shortage of fighters and rangers back in the day.  People wanted to be wizards and rerolled into fighters or thieves when they decided they wanted to do something...literally.  You had your one spell per day at level 1.  Nobody wanted to be "stuck" playing the cleric because while you were a spell caster, you should only use your spells for healing, bot.  And you couldn't use swords because you were opposed to shedding blood, and pretty much every magic weapon drop, ever, was a longsword.  Technically, clerics abided by Vancian restrictions too, but I never saw a table that ruled it that way.  Every table I played at played clerics as though they were modern spell slots.  The thought was, you're praying to your god for something to happen.  You should be able to ask on the fly what effect you wanted.  But if you ever cast something other than heals, your party would give you side eye.

The new system is way better than true Vancian magic.  I do wish that opposition schools were brought back to rein in wizards a bit.  Man, 2e wizards lived a rough life.  People complaining about rangers and such never had 3 hps and a single magic missile spell per day, and it shows.

Sounds boring. You sit in the back waiting around while others fight. Halfway through the fight you realise that your one spell is actually useful, cast it, and then that's you done for the day in terms of real usefulness?

Sounds really bad.

To me, 'Vancian' simply translates into 'illogical game design deemed necessary for balancing purposes'. And it's not wrong, either. I liked how 3.5 psionics worked (decidedly un-Vancian), but it was a messed up ... well, mess. 

Vancian magic refers to the way magic worked in Jack Vance's Dying Earth stories, which also is how magic worked in 1E.  Basically, you had to pick a spell for each spell slot when memorizing spells.  For example, if you had three level three slots, you could memorize Fireball, Fireball, and Haste.  Once you cast Fireball twice, or Haste once, you couldn't cast those spells again.

Quote from Linklite >>

Sounds boring. You sit in the back waiting around while others fight. Halfway through the fight you realise that your one spell is actually useful, cast it, and then that's you done for the day in terms of real usefulness?

Sounds really bad.

 It was.  I tried it once.  Died in the first session when I tried to hit something with my dagger after I got bored.  Made a new fighter.  It got better if you managed to get levels, but everyone else leveled up faster than you did too.  A wizard needed something like 2500 exp to reach level 2.  A fighter was 2k-ish.    So your fighter who got to swing his sword every turn would hit 2k exp and level up to two.  And you, who were there for every combat, was still level 1 because you didn't reach your level cap yet.  You'd eventually be a full level or more behind everyone else, showing up for every session, earning every bit of exp they did...just because you were a wizard.

Now when you got the thing to higher levels, it really wasn't so bad.  You had enough spell slots to memorize a decent loadout of stuff, and you usually didn't have a ton of combat every day because people ran out of health, and the cleric had to recharge you because...well you only recovered one HP per sleep; this is part of why clerics never really got to cast their other spells.  The fighters and rangers (nobody ever played paladins, because nobody who rolled a 17 was wasting it in charisma to be locked into being lawful good) would run in and bash things.  Thieves would try to backstab things.  Clerics at least got to bash things with their mace, but wizards?  Tough sledding for those chaps.  I didn't have the fortitude to stick it out.  Maybe if we had cantrips, or could at least use all mage weapons equally (had to buy proficiency with that dagger, so I couldn't even just pick up a sling and use it without a big penalty) it would have been more bearable.  If I still had to play that system, I'd 100% take a sling over my dagger because chucking d4s from range is way better than sucking with a d4 in melee, but seriously, I'd never want to see Vancian magic return.

Quote from Linklite >>

Sounds boring. You sit in the back waiting around while others fight. Halfway through the fight you realise that your one spell is actually useful, cast it, and then that's you done for the day in terms of real usefulness?

Sounds really bad.

 
you aren't wrong by a long-shot.  It could be so dull to play a caster back in the day. you were also so squishy. I may have started with this kind of magic, but i don't miss it.

Quote from 6thLyranGuard >>

Quote from Xalthu >>

I said both, since that’s the way it used to work. 
I played starting in becmi, and or was never, to my knowledge, explicitly called that in any official books; it just was that. Based, btw, on the Dying Earth series by Jack Vance. 

The current system isn’t really vancian anymore, imo. In the early editions, if you thought you’d cast a spell more than once in a day, you had to memorize it more than once. So if you had 2 level 1 spell slots, say you memorized magic missile and burning hands. If you cast magic middle, you couldn’t cast it again. The only option left for you was to cast burning hands. If you thought you’d might need 2 magic missiles, you’d memorize that spell twice, and no other spells. 
Also, there was no upcasting, or rituals or cantrips. Casters really had to plan ahead. And clerics pretty much had to memorize heal spells, and only heal spells. Since there was no upcasting, there was just a different, more powerful version of cure wounds with each spell level. Maybe you could sneak a hold person in there eventually  

Personally, while I wouldn’t want to go back to it, I do think it’s one of the changes that contributes to the martial/caster imbalance. The new way really lets casters be more prepared for more situations. 

 Actually, the change has significantly flattened the curve compared to older editions.  Wizards started out as significantly weaker than martials but progressed considerably faster and while they did have to prepare spells, they had enough options that it rarely presented a serious problem unless you tried to seriously overspecialize.

Also, magic item creation was a significantly bigger aspect of previous editions, which meant that casters could make scrolls, potions, and wands to function as ways to extend their powers and improve their versatility.

 I get what you're saying but I disagree. IMO, one of the things that makes casters so much stronger in later editions is the swiss-army knife style of being much more likely to have the right utility spell ready to overcome lots of different problems. Under the pure vancian model, you still might, but you usually had much fewer different spells prepped, and so were less likely to have the right one ready. Though on the up side, it really encouraged preparing, as you were much better off knowing what you were getting into so you might have the right spell ready.

And, of course, casting time was another big factor, which, iirc, was also an aspect of the vancian system. (For those who don't know, in 1e, rounds were broken up into segments, and spells would have a casting time in segments. You'd start casting at one point in the round, then actually finish casting X segments later on, sometimes a round or more later on, and if you took damage in between, the spell just failed.) Dropping that, I think, overall improved the game, but also boosted caster power.

I remember magic item creation cost you XP, which kept your level lower if you were making them. (And magic users already needed more xp to level up than other classes.) Though I don't remember if that applied to scrolls.  I do remember lots of magic items requiring the permanency spell, which cost 1 point of constitution every time you cast it.

Quote from Linklite >>

Sounds boring. You sit in the back waiting around while others fight. Halfway through the fight you realise that your one spell is actually useful, cast it, and then that's you done for the day in terms of real usefulness?

Sounds really bad.

Pretty much. If you were a level 1 magic-user, once you cast magic missile, you could practically go home, your session was over. Technically, you could throw darts, or daggers as crzyhawk said, but that was rarely useful.

I will say that there was no martial/spellcaster imbalance because while they could throw a spell at every problem, they had to foresee the issue and memorize the spell for it.  if anything it was balanced against the spellcaster because it was just so punishing for those few moments when the stars aligned and you could really shine.

Quote from Xalthu >>

Quote from 6thLyranGuard >>

Quote from Xalthu >>

I said both, since that’s the way it used to work. 
I played starting in becmi, and or was never, to my knowledge, explicitly called that in any official books; it just was that. Based, btw, on the Dying Earth series by Jack Vance. 

The current system isn’t really vancian anymore, imo. In the early editions, if you thought you’d cast a spell more than once in a day, you had to memorize it more than once. So if you had 2 level 1 spell slots, say you memorized magic missile and burning hands. If you cast magic middle, you couldn’t cast it again. The only option left for you was to cast burning hands. If you thought you’d might need 2 magic missiles, you’d memorize that spell twice, and no other spells. 
Also, there was no upcasting, or rituals or cantrips. Casters really had to plan ahead. And clerics pretty much had to memorize heal spells, and only heal spells. Since there was no upcasting, there was just a different, more powerful version of cure wounds with each spell level. Maybe you could sneak a hold person in there eventually  

Personally, while I wouldn’t want to go back to it, I do think it’s one of the changes that contributes to the martial/caster imbalance. The new way really lets casters be more prepared for more situations. 

 Actually, the change has significantly flattened the curve compared to older editions.  Wizards started out as significantly weaker than martials but progressed considerably faster and while they did have to prepare spells, they had enough options that it rarely presented a serious problem unless you tried to seriously overspecialize.

Also, magic item creation was a significantly bigger aspect of previous editions, which meant that casters could make scrolls, potions, and wands to function as ways to extend their powers and improve their versatility.

 I get what you're saying but I disagree. IMO, one of the things that makes casters so much stronger in later editions is the swiss-army knife style of being much more likely to have the right utility spell ready to overcome lots of different problems. Under the pure vancian model, you still might, but you usually had much fewer different spells prepped, and so were less likely to have the right one ready. Though on the up side, it really encouraged preparing, as you were much better off knowing what you were getting into so you might have the right spell ready.

And, of course, casting time was another big factor, which, iirc, was also an aspect of the vancian system. (For those who don't know, in 1e, rounds were broken up into segments, and spells would have a casting time in segments. You'd start casting at one point in the round, then actually finish casting X segments later on, sometimes a round or more later on, and if you took damage in between, the spell just failed.) Dropping that, I think, overall improved the game, but also boosted caster power.

I remember magic item creation cost you XP, which kept your level lower if you were making them. (And magic users already needed more xp to level up than other classes.) Though I don't remember if that applied to scrolls.  I do remember lots of magic items requiring the permanency spell, which cost 1 point of constitution every time you cast it.

Quote from Linklite >>

Sounds boring. You sit in the back waiting around while others fight. Halfway through the fight you realise that your one spell is actually useful, cast it, and then that's you done for the day in terms of real usefulness?

Sounds really bad.

Pretty much. If you were a level 1 magic-user, once you cast magic missile, you could practically go home, your session was over. Technically, you could throw darts, or daggers as crzyhawk said, but that was rarely useful.

 I'd forgotten the con cost for permanency.  I do remember at the  time thinking who the heck's spending all this con to create all these longsword+1

Quote from crzyhawk>>

 I'd forgotten the con cost for permanency.  I do remember at the  time thinking who the heck's spending all this con to create all these longsword+1

 A long sword made sense to me.  But how many people did it take to make a bag of 20 +1 sling bullets?

Quote from Xalthu>>

Quote from 6thLyranGuard>>

Quote from Xalthu>>

I said both, since that’s the way it used to work. 
I played starting in becmi, and or was never, to my knowledge, explicitly called that in any official books; it just was that. Based, btw, on the Dying Earth series by Jack Vance. 

The current system isn’t really vancian anymore, imo. In the early editions, if you thought you’d cast a spell more than once in a day, you had to memorize it more than once. So if you had 2 level 1 spell slots, say you memorized magic missile and burning hands. If you cast magic middle, you couldn’t cast it again. The only option left for you was to cast burning hands. If you thought you’d might need 2 magic missiles, you’d memorize that spell twice, and no other spells. 
Also, there was no upcasting, or rituals or cantrips. Casters really had to plan ahead. And clerics pretty much had to memorize heal spells, and only heal spells. Since there was no upcasting, there was just a different, more powerful version of cure wounds with each spell level. Maybe you could sneak a hold person in there eventually  

Personally, while I wouldn’t want to go back to it, I do think it’s one of the changes that contributes to the martial/caster imbalance. The new way really lets casters be more prepared for more situations. 

 Actually, the change has significantly flattened the curve compared to older editions.  Wizards started out as significantly weaker than martials but progressed considerably faster and while they did have to prepare spells, they had enough options that it rarely presented a serious problem unless you tried to seriously overspecialize.

Also, magic item creation was a significantly bigger aspect of previous editions, which meant that casters could make scrolls, potions, and wands to function as ways to extend their powers and improve their versatility.

 I get what you're saying but I disagree. IMO, one of the things that makes casters so much stronger in later editions is the swiss-army knife style of being much more likely to have the right utility spell ready to overcome lots of different problems. Under the pure vancian model, you still might, but you usually had much fewer different spells prepped, and so were less likely to have the right one ready. Though on the up side, it really encouraged preparing, as you were much better off knowing what you were getting into so you might have the right spell ready.

And, of course, casting time was another big factor, which, iirc, was also an aspect of the vancian system. (For those who don't know, in 1e, rounds were broken up into segments, and spells would have a casting time in segments. You'd start casting at one point in the round, then actually finish casting X segments later on, sometimes a round or more later on, and if you took damage in between, the spell just failed.) Dropping that, I think, overall improved the game, but also boosted caster power.

I remember magic item creation cost you XP, which kept your level lower if you were making them. (And magic users already needed more xp to level up than other classes.) Though I don't remember if that applied to scrolls.  I do remember lots of magic items requiring the permanency spell, which cost 1 point of constitution every time you cast it.

Yeah, that depended on which edition specifically you're talking about, but at high levels the amount of XP needed to create things that weren't magic weapons or armor tended to be relatively trivial.

Really, you compare a 20th level wizard from 2nd Edition or 3.5 Edition and they would absolutely smoke a 5E wizard and it would not be a close contest.  The only thing that really slowed down high level casters in old editions was Magic Resistance, when monsters had a flat chance of spells simply failing to affect them entirely rather than the simple bonus to saving throws they get in 5E.  Yes, the old style of spell preparation was more difficult, but the classes were significantly stronger if you knew what spells to learn.

Quote from Xalthu >>

Quote from crzyhawk>>

 I'd forgotten the con cost for permanency.  I do remember at the  time thinking who the heck's spending all this con to create all these longsword+1

 A long sword made sense to me.  But how many people did it take to make a bag of 20 +1 sling bullets?

 IIRC, just one: magic ammo was cheap to make and could be made in batches.

Quote from 6thLyranGuard >>

Quote from Xalthu >>

Quote from crzyhawk>>

 I'd forgotten the con cost for permanency.  I do remember at the  time thinking who the heck's spending all this con to create all these longsword+1

 A long sword made sense to me.  But how many people did it take to make a bag of 20 +1 sling bullets?

 IIRC, just one: magic ammo was cheap to make and could be made in batches.

 But you needed one permanency spell per sling bullet, iirc. And since it cost a point of constitution per cast, it would add up.