noun: concept; plural noun: concepts
an abstract idea; a general notion.
"structuralism is a difficult concept"
synonyms: idea, notion, conception, abstraction; More
It’s exactly that. An abstract idea that pertains to a particular type of tricks, movements, or anything else.
It probably means one of two things in the context you are seeing it.
A trick is incomplete. Someone is filming just to show off their progress with it.
Someone found something neat that works in one mount (Wrist Mount, 1.5, Double or nothing. You get it) And they are trying to apply the same movement or trick to different mounts. They are working with it and trying to develop it into something unique.
As far as concepts for you to explore. I would look at Straight Jacket. It’s a neat concept/substyle. Basically, just do everything with your arms crossed. Charles haycock, Isaac Sams, and Sid Seed are good players to watch for inspiration regarding this.
Hope I helped!