means A revolving spool used to wind up something flexible — film, fishing line, thread — or by extension a length of that wound-up material, like a movie reel or the dizzy stagger of someone who 'reels' from a blow.

from From Old English 'hrēol,' a device for winding thread, traced back to a Proto-Germanic root tied to spinning and turning. The dance called a reel — and the verb meaning to whirl or stagger — likely sprang from the same sense of going round and round. The fishing reel and film reel are later, literal-minded heirs to that ancient turning spool; the social-media 'Reel' is the newest cousin, borrowing the name of the spinning film it imitates.