This isn’t really a linguistic annoyance but I’ve not used that category for a while.

Anyway I was tickled by the title of a listing (now vanished) on eBay. (PHOTO DUMBARTON CENTRAL RAILWAY STATION VIEW IN THE 1960`S WITH AN EMU IN VIEW.)

“An emu?” I thought.

Then after a second I realised it must be train-buff speak for electrical multiple unit.