Outlier
A post that substantially beat its own channel's norm: the only kind of hit worth studying.
An outlier is a post that performed far above the baseline for the account that published it. Not far above the internet's baseline, and not far above a competitor's: its own.
Defining it relative to the channel is what makes it useful. A video with fifty thousand views is a catastrophe on a channel that normally does five hundred thousand and a landmark on one that normally does two thousand. Only the second is telling you something you can act on.
Outliers are worth studying because they're the closest thing to a natural experiment you get for free. Everything else about the channel (the audience, the subscriber base, the posting cadence, the brand) was roughly constant. Something about that specific post was different. Finding out what is the entire job.