Where is this referred to as 'a dap'? Looking on etymonline, I see a different meaning. I've never heard this term before.

dap(n.)  

fist-bump greeting, in African-American popular culture by 1972, with various theories as to origin and name meaning. Probably imitative (dap was used in 19c. for the bounce of a ball or the skip of a stone on water). Dap, meanwhile, is listed in the DAS as African-American vernacular c. 1950 for "aware, up to date," also "stylish, well-dressed," in the latter case at least a shortening of dapper. Controversial during the Vietnam War when used by U.S. soldiers, as it often was regarded by whites as a ritual act of black solidarity.  

https://www.etymonline.com/word/dap

How to dap

The dap is a friendly greeting between 2 people to express solidarity.
It includes a wide variety of gestures, but it can be any handshake you have with a close friend. Most people create their own dap with unique snaps, slaps, and fist bumps—there’s no “right” or “wrong” way to dap someone up![1]

I don't dap beyond fist/elbow bumbing, it would feel like appropriation if I tried. So, I can only point to sources. That hand clasp is very common from the ones I've seen in my sheltered life.

The elbow bump is because I'm often in gloves covered in chemicals... So elbows, if it has to be anything... Don't dap me up, it's awkward.

wholesome as fuck AND I learned a new word! Quality post.

I appreciate the response, but I'm more curious about who is using this term to mean something other than what I found, and where and since when? It wasn't used in my area of the US before I left more than a decade ago (unless maybe the university kids were using it and I didn't interact with them enough). I now live in rural eastern Asia, so basically zero chance I would hear anyone say this organically anywhere.

Oh, who: Americans, see sources I guess they're all American. Where: I've heard it used in Britain too, so 'the American hegemonic cultural west' I guess. Since when: not a clue.

For what it's worth, I heard the term 'fist bump' specifically for the act of fist bumping long before I heard of 'daping up'. When I hear 'dap' it has almost always, I think actually always but I can't be sure, included one of those hand clasps. A fist bump is just a 'fist bump'. It's strange what percolates out from the dominant culture.

When I hear dap up I just think of that 'in the hood' series time stamp 2:47. Dap up, that hand clasp thing, no fist bump.