Well, to start, we actually already do have a definition tag; however, in the case where you don't know the name of what you're looking for, it's probably better to use terminology or notation. Let's compare and contrast.

A canonical question for definition would be something like

I'm reading the paper A Treatise In Frustration (A. Gruber, Journal of Fake Group Theory, January 2019), and I'm having trouble understanding the following definition.

Def. A group $G$ is said to be annoying if $[G,G]\ne\{[a,b]:a,b\in G\}.$

I've looked everything up, and I understand that $[G,G]$ is defined as the subgroup generated by $\{[a,b]:a,b\in G\}$, not just the set $\{[a,b]:a,b\in G\}$. But in every example I can think of, these are equal, how is it possible that they couldn't be? What is an example of an annoying group? What does it mean?

A canonical question for terminology would be something like

Hi Math StackExchange. I'm a programmer whose job is to abelianize groups for the reputation-backed securities market, and boy do I have an irritating problem. Sometimes I run into these groups where I calculate $\{[a,b]:a,b\in G\}$ and it turns out not to be a subgroup, so my program crashes! Some examples include $\operatorname{SL}_2(\mathbb{R})$, the free group on $2$ letters, and a couple of finite groups with order 96. Is there some kind of established term for these groups so that I can avoid them in the future?

A canonical question for notation would be something like

I met a math major at the bar the other day and after texting her 36 times in a row, she sent me this:

 

$\emptyset \ne [G,G]\setminus\{[a,b]:a,b\in G\}$

 

I can't begin to unpack this because I don't even know what those brackets mean. I'm in way over my head here, you guys. What do $[a,b]$ and $[G,G]$ mean?

It's also a good idea to pair these tags with reference-request in the case that you're looking for an official source, math-history if you're wondering who came up with something first, or motivation if you're wondering why the definition matters or its relevance in the grander scheme of things. Along with tagging the relevant field(s) of mathematics, this should be draw enough attention to your question to get you what you're looking for.

Well, to start, we actually already do have a definition tag; however, in the case where you don't know the name of what you're looking for, it's probably better to use terminology or notation. Let's compare and contrast.

A canonical question for definition would be something like

I'm reading the paper A Treatise In Frustration (A. Gruber, Journal of Fake Group Theory, January 2019), and I'm having trouble understanding the following definition.

Def. A group $G$ is said to be annoying if $[G,G]\ne\{[a,b]:a,b\in G\}.$

I've looked everything up, and I understand that $[G,G]$ is defined as the subgroup generated by $\{[a,b]:a,b\in G\}$, not just the set $\{[a,b]:a,b\in G\}$. But in every example I can think of, these are equal, how is it possible that they couldn't be? What is an example of an annoying group? What does it mean?

A canonical question for terminology would be something like

Hi Math StackExchange. I'm a programmer whose job is to abelianize groups for the reputation-backed securities market, and boy do I have an irritating problem. Sometimes I run into these groups where I calculate $\{[a,b]:a,b\in G\}$ and it turns out not to be a subgroup, so my program crashes! Some examples include $\operatorname{SL}_2(\mathbb{R})$, the free group on $2$ letters, and a couple of finite groups with order 96. Is there some kind of established term for these groups so that I can avoid them in the future?

A canonical question for notation would be something like

I met a math major at the bar the other day and after texting her 36 times in a row, she sent me this:

$\emptyset \ne [G,G]\setminus\{[a,b]:a,b\in G\}$

I can't begin to unpack this because I don't even know what those brackets mean. I'm in way over my head here, you guys. What do $[a,b]$ and $[G,G]$ mean?

It's also a good idea to pair these tags with reference-request in the case that you're looking for an official source, math-history if you're wondering who came up with something first, or motivation if you're wondering why the definition matters or its relevance in the grander scheme of things. Along with tagging the relevant field(s) of mathematics, this should be draw enough attention to your question to get you what you're looking for.