If this was already officially answered by an official type, I apologize as my search-fu has failed me.
After finding no spells that give a direct buff to "skill checks" I started reading and researching. With this being said..
Am I correct in my reading of the PH that all a skill check is is, one of the 3 main rolls, an Ability check with a proficiency bonus (in case of skilled) or double proficiency bonus (In case of expertise) so Guidance gives the +1d4 to an ability check (which can be a skill check)?
This is essentially correct. A skill check is an ability check that happens to be associated with a given skill. Anything that provides a bonus to an ability check affects skill checks to, Guidance and Enhance Ability are classic examples of this.
There are spells like Pass Without Trace that enhance a specific skill, but usually if something enhances all skill checks they generalize it to ability checks.
Yes a "skill check" is an ability check. So any effect that applies to ability checks applies to skills.
Initiative rolls and tool checks are also ability checks, but not skills. The DM can also ask you to make an ability check that doesn't benefit from any kind of proficiency, but this is uncommon (I don't think anything official ever mentions such a roll specifically [edit], but it is a consequence of all the stuff Sposta said below⬇️).
There is no such thing as a “skill check” this edition, there are only “ability checks.” If the creature is proficient in a relevant skill, they can add their PB to the Ability Check. If they have double proficiency in that skill, they can add twice their proficiency bonus to that Ability Check. Regardless, they are all “Ability Checks.”
I still think it's fair to use the term "skill check" as shorthand for an ability check that is modified by one's proficiency in a skill, as opposed to a direct ability check, such as with counterspell, or the frost giant (variant). I think the colloquial distinction eliminates more confusion than it adds.
That being said, what IamSposta said is correct. In the end, they are both ability checks.
I still think it's fair to use the term "skill check" as shorthand for an ability check that is modified by one's proficiency in a skill, as opposed to a direct ability check, such as with counterspell, or the frost giant (variant). I think the colloquial distinction eliminates more confusion than it adds.
That being said, what IamSposta said is correct. In the end, they are both ability checks.
Oh, sure, I also generally refer to “skill checks” in my home group. It is a convenient shorthand, no doubt.
If this was already officially answered by an official type, I apologize as my search-fu has failed me.
After finding no spells that give a direct buff to "skill checks" I started reading and researching. With this being said..
Am I correct in my reading of the PH that all a skill check is is, one of the 3 main rolls, an Ability check with a proficiency bonus (in case of skilled) or double proficiency bonus (In case of expertise) so Guidance gives the +1d4 to an ability check (which can be a skill check)?
This is essentially correct. A skill check is an ability check that happens to be associated with a given skill. Anything that provides a bonus to an ability check affects skill checks to, Guidance and Enhance Ability are classic examples of this.
There are spells like Pass Without Trace that enhance a specific skill, but usually if something enhances all skill checks they generalize it to ability checks.
Fangeye is 100% correct, but if you would like to learn a little more on the subject, this is a good article: https://dnd.wizards.com/sage-advice/ability-check
Yes a "skill check" is an ability check. So any effect that applies to ability checks applies to skills.
Initiative rolls and tool checks are also ability checks, but not skills. The DM can also ask you to make an ability check that doesn't benefit from any kind of proficiency, but this is uncommon (I don't think anything official ever mentions such a roll specifically [edit], but it is a consequence of all the stuff Sposta said below⬇️).
There is no such thing as a “skill check” this edition, there are only “ability checks.” If the creature is proficient in a relevant skill, they can add their PB to the Ability Check. If they have double proficiency in that skill, they can add twice their proficiency bonus to that Ability Check. Regardless, they are all “Ability Checks.”
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Thank you all for your time and assistance on this clarification. Greatly appreciate it.
I still think it's fair to use the term "skill check" as shorthand for an ability check that is modified by one's proficiency in a skill, as opposed to a direct ability check, such as with counterspell, or the frost giant (variant). I think the colloquial distinction eliminates more confusion than it adds.
That being said, what IamSposta said is correct. In the end, they are both ability checks.
"Not all those who wander are lost"
Oh, sure, I also generally refer to “skill checks” in my home group. It is a convenient shorthand, no doubt.
DDB Buyers' Guide
Hardcovers, DDB & You
Content Troubleshooting
Epic Boons on DDB