Blame language evolving over time rather than OP, octocopter is a widely-used term for '8 propellor drones'.

A nit pick with your post - you use the word 'ambiguous' but really this is from the latin root 'ambiguus' so we don't need the supurflous 'o' in between the two u's.

Well I was confused by it! I was expecting an article on amateur semiconductor fabrication. Granted, that was due to my misreading it as 'optocoupler'.