A better example would be the question "What do Brits call a 'comforter'" - to which the obvious answer is "Someone who gives comfort", and not, and the questioner needs to know: (a)a child's dummy or (b)a quilt (or possibly duvet - I've never been able to work out exactly what function an American bed comforter performs).

This morning's example of the genre was "What do you guys call a flashlight?"