I've noticed that over time alot of people dont actually understand that these terms dont really exist in D&D. Even though you can trace similarities to them and with what they do.

For instance let's look at debuff. A quick search reveals that its defined by anything that negatively affects a character. Much of these go on to give examples of such things. The problem is that in D&D very rarely are you doing something to a creature that physically changes its abilities. Infact what you are actually effecting the majority of the time are action economy. 

What do I mean by action economy?  Well it's simple. Let's look at bane for instance. Bane does not physically change anything about a creature its cast on. What it does do is effect the rolls it takes. This means that even with Bane cast on something it can literally have no effect what so ever on that creatures ability to hit you or save against you depending on various rolls. This does not effect the creature but instead effects the nature of probability or the economy of action.

A buff also generally doesn't make you stronger though there are a few abilities that do for a period of time. The spells that are generally considered buff spells dont actually buff anything but instead effect probability of success thus effecting the economy of action and not the physical creature.

Tanks and Agro also are also other terms pulled directly from MMOs. There is no ability in D&D that let's you pull the attention of a creature and let's you party continue to deal damage to said creature. I'm sure right now some people reading this are like Compelled Duel does. No it doesnt. The second a party member does anything to a creature that is the subject of the spell the spell ends. In D&D "tanking" and "agro" have really nothing to do with abilities but are about two other things completely. Survivability and postioning.

Tanks and Agro are used much the same way that buffs and debuffs are used in D&D now. Even though what they actually affect in game is generally compeltely different than how its used in MMOs.

Why there has been a modern trend to throw various MMO terminology into D&D and assume it's the same is absolutely beyond me. Personally I think it erodes at the game especially when having discussions on the mechanics of it. 

I don't see a distinction between "affecting the action economy" and "affecting the creatures". Bane, for example, makes the creature worse at attacking and resisting saving throws, by a d4. The die rolls are what, in-game, represent the abilities of the creature.

The terms make perfect sense to me. "Buff" - a positive spell, something that helps its target (excluding healing, which is separate). Guidance, Haste, Spider climb, and many others. Debuff - something that hurts its target without dealing damage. Faerie Fire, slow, etc. "Tank" - a character that's built to be able to withstand lots and lots of attacks.

No idea about aggro, I haven't heard that used in D&D.

Anyway, sorry if outside MMOs these words mean something different. I've never played MMOs and don't plan to, and I can understand what people mean by "Buff", "debuff", and "tank" in D&D 5e perfectly fine.

You’re misusing the term “action economy.” Action economy refers to how much a character can do and how often they can do it. Bane makes a character worse at doing things without affecting how many actions they can take. It’s a straight-up debuff and has nothing to do with the action economy.

On the other hand, a mindwitness’s slow ray makes it so that an affected character can only take an action or a bonus action, but not both. Also obviously a debuff, but THAT actually affects the action economy.

Buff and debuff are definitely being used just fine in D&D. They are spells and effects that make characters better or worse at something (usually damage or accuracy, but not necessarily) which fit their definitions.

Action economy refers to the amount of actions you are taking not necessarily the efficiency of those actions.

Tank is used to refer to characters that can take a lot of attacks (by being hard to hit, having a lot of HP, and/or having damage resistance). There is no aggro in D&D (and I have never heard anyone use the term while talking about D&D) so the role of tank doesn't 1-to-1 with MMOs, but they are otherwise stated similarly and there are ways to encourage enemies to target the tank, so it is easier to use the term most people already know rather than make up a new term.

I think the only term that doesn't translate well to D&D is 'DPS' because it literally means "damage per second", but even then, it's good shorthand for a high damage output character. DPR (damage per round) is a common substitute.

That being said, a lot of terms translate adequately because they're about conveying a general idea, not a specific mechanic or feature:

• Buff = makes things better
• Debuff = makes things worse
• Tank = can get hit a lot without going down
• Agro = can make things want to hit it/drawing attention
• DPS = does a lot of damage very quickly
• Action economy = literally a D&D design term that refers to how much you can do in one turn

action economy can also refer to how much each side in combat can do during 1 round of iniative 

Well that is the inherent problem they are general distinctions. None of these term apply in any mechanical nature.

The original creators of the game have even explicitly stated that these terms dont function in D&D for much of the reasons I stated.

In MMOs buffs or debuffs directly effect a creature. In D&D very, very few things directly do this and even less the players have control of. In D&D the bulk of what people consider buffs or debuffs indirectly effect creatures. By indirectly we are refering to probability and chance. The very nature of D&D.

In MMOs tanks are a class that draw attention of agro and can survive damage. While this can be translated in a sense of surviving damage the nature of drawing attention mechanically while the rest of the party deals damage is not possible at all.

Action Economy in D&D refers to both how much y0u can do and what is done in a single turn. By using spells such as bane, slow, etc. You are effecting the Action Economy not the character. You effect actions taken, chance to hit chance to deal damage etc. This all falls under action economy.

The original creators of the game have even explicitly stated that these terms dont function in D&D for much of the reasons I stated.

The original creators who made the games before MMO's existed? I'm pretty sure Gygax et al never commented on MMO terminology

In MMOs buffs or debuffs directly effect a creature. In D&D very, very few things directly do this and even less the players have control of. In D&D the bulk of what people consider buffs or debuffs indirectly effect creatures. By indirectly we are refering to probability and chance. The very nature of D&D.

This isn't a valid definition of a buff/debuff. In MMO terminology, an ability that increases your chance of proc'ing a crit from 6% to 7% is still a buff. Also there are tonnes of spells and abilities that directly affect PCs; bless, guidance, enhance ability, magic weapon, elemental weapon. These are all buffs as they make the PCs more effective (that's what buff means, to increase the effectiveness). Likewise, Bane, Hex, Slow are all debuffs because they make enemies less effective.

In MMOs tanks are a class that draw attention of agro and can survive damage. While this can be translated in a sense of surviving damage the nature of drawing attention mechanically while the rest of the party deals damage is not possible at all.

That's not true, there are abilities and spells that can draw attention long enough to allow the party to inflict damage. For example, Compelled Duel can lock down an enemy long enough to allow the rest of the party to re-position and deal damage (which does end the spell, but it can just be recast).

You are creating a bunch of strangely specific definitions that disagree with their actual usage in order to support your argument.

I learned to play Dungeons & Dragons from the old Infinity Engine video games, so I've never had D&D not gamified in my brain and it's never detracted from my experience. I'm sure they had Grognards back in 1998 saying The Sky Is Falling and why isn't this like the Gold Box games and kids today are spoiled with their Compact Discs and Pentium computers they'll never learn how to play REAL D&D now blah blah

As far as terminology goes, I just don't like Aggro. The rest of the terms make it simple to explain the D&D equivalent of similar concepts. Aggro is a specific game mechanic for raiding in World of Warcraft, where in D&D your front lines dude who can take a beating pretty much has to give a not necessarily strictly mechanical reason/incentive to the other front lines dudes.

That's not true, aggro is a general term for inciting an enemy to attack a specific (usually more durable) character. The term was used across the MMO board (Everquest II and RF Online for me) as well as some board game design (Zombicide uses the mechanism)

Aggro applies to way more than WoW. A heavily armored paladin or cleric can draw aggro by dashing through a room of enemies and drawing all of their attention away from the where the rest of the party is. With the enemy's attention on the loud armored combatant, the PCs are set up for Sneak Attack, flanking, or a relatively safe opening barrage of ranged spells/attacks. Just because it's not a video game doesn't mean that similar combat tactics can't apply.

As a general term, it's used to describe a specific mechanic. Aggro on a mechanical level works differently in Final Fantasy XIV than in World of Warcraft, for example. I feel this muddies the waters when trying to explain how it works in D&D. As a DM, I'd never make monsters so dumb as to always attack one dude over and over again, the dude they can't hit, the dude that won't die.

The specifics of the mechanic always vary from game to game, but the general concept is the same; "make the enemy attack who you want them to attack, usually yourself". This can be done in D&D through spells like Command or Compelled Duel, or through use of skills such as Intimidation

Even an intellegent creature will likely focus on the PC in their face wailing on them, at least until someone else becomes a bigger threat. Obviously the mechanics vary from other games, but the overall concept remains in place.

OK, I see you're pretty invested in this, but as the DM, I'm doing the thinking for my monsters, who have hopes, dreams, aspirations, and they aren't just a bunch of numbers like a raid boss. They're going to disable the biggest existential threat through any means necessary, and that doesn't fall into the MMO DPS/Tank/Heals paradigm.

I never implied I was running them as a bunch of numbers, instead quite the opposite. The two spells I mentioned are mechanical effects that can force an enemies behaviour, while skills such as intimidation are directly RP tactics that only work if you run mosters intelligently. For example, you could aggro the leader of an orc tribe that values strength by issuing them a challenge, claiming they are too weak to lead. That is still aggro, but done in an intelligent way with a high degree of immersion and verisimilitude.

Also, I wasn't ascribing a paradigm, I was saying the terminology is valid. In fact, I believe the tank/healer/support/dps mentality in terms of filling roles and party composition is largely inapplicable to 5e. But that doesn't render the terms useless in describing functions and tactics.

No one is saying it operates exactly like a MMO, but like it or not, the concept of aggro exists in D&D. Certainly not as effectively as a video game, but it exists nonetheless. Hell, even "pulling" works in D&D, by using Command, Compell, or Dominate to take control of a creature and move it away from a group for a stealthy takedown.

At the end of the day, these are just words bleeding over from gaming because there has been a huge influx of MMO players into the tabletop realm. When they use these terms, everyone knows what they mean, even if mechanically they are not identical. And if the players don't understand that, it is the DM's responsibility to educate them on how it works in this game.

In short, if you don't like the terms, don't use them. But they're not hurting anything either.

You seem to be not understand what directly effecting a pc vs effecting chance means.

Directly effecting is a spell like feeble mind that directly reduces your intelligence and charisma to 1. This is directly effecting stats.

Directly effecting is not improving you're odds of success. Advantage/disadvantage, addition d4s etc. Are not direct effects but indirect effects. Bless, guidance, and enhance ability all fall under this. 

This is a discussion on the mechanics and thus it is very important to seperate what effects chance and what is literally a boost to stats.

Look I'm not saying the terminology is  not understandable when used. I'm saying from a mechanical point it's not the same. You yourself pretty much says the same later on. The bulk of the reason I started this discussion is I have recently first hand witnessed many people believing it works the same. It doesnt. Simple as that.

As for Aggro I've noticed some people are saying compelled duel, and command and stuff is similar to what tanks in MMOs do. I'm sorry it's not. On a very very general comparison I'll give you it can be related but that's as far as it goes. In D&D everything for the most part boils down to battlefield control and action economy. Battlefield control for "tanks" in D&D is more often than anything only positioning. I'd know this specifically as for 15 years my main go to class is S&B Paladins. Positioning on keeping the enemy from getting past you is how to protect your squishy spell casters. Nothing Agro about it.

When we start comparing things like Compelled Duel and command and trying to compare then to MMO terms you miss the simplest thing. In D&D spells can fail. It's not a reliable way to do it. Furthermore very Rarely is a singular person in D&D going to stand toe to toe with a big bad for any period of time like the do in MMOs. Especially cause in these MMO games where they do this the "Healer" is focused on keeping the "tank" alive to do this while the party damages it or adds. Yes compelled duel and command both allow you to target a creature to single them out for a time. In commands sense a single round. In compelled duel sense a minute or until your party does anything to it what so ever. This is fundamentally different from how Aggro and pulling work in MMOs.

Anyways this discussion here as jdahveed stated is more so to put out there while there are similarities between these in D&D and MMOs they operate compeletely different from one another both in function and in mechanics.

The thing about language is that it changes. The terms we use in D&D have slightly different but very similar meanings as in MMOs. It's the same as how classes in different games can have the same name, but different mechanics and strategies.