Don't look it up, or read other's answers. Just explain what you understand by the word "meme", in your own words. The idea is to explore the different interpretations.
I actually know what meme means even outside of the context that most people associate with it.
Sheldon Cooper of TDF.
Richard Dawkins.
More often than not, memes are mostly built upon trending topics. But this is not always the norm, sometimes older media could gain mainstream attention and become meme-worthy like Joseph Ducreaux's self portrait became a meme about rap lyrics transliterated as Shakespearean prose.
Webcomics are not memes by default. But a particular webcomic could capture the imagination of everyone in such a way that it becomes a so called "exploitable" that everyone can repurpose to apply to different subject matters, then it becomes a meme.
Very. Or at least it must be popular enough among a certain demographic. Inside jokes of certain communities could also be called memes, but those will be confined to those communities and might not make sense to an outsider. For example, hardly anyone uses the term "chicken tendies" outside of 4chan.
The idea represented by the image macro is the meme. The image is just a medium. For example, people read confession bear memes for the personal stories people write on it, the image of the bear itself merely represents the nature of the message or the expression of the person writing the text.
On their own, no. But with a combination of popularity and meaning, yes.
The meme is the idea represented by the template. The image and text by itself is simply a medium and gives context to the message passed by it.
Yes. Also look up "youtube poop".