36 out of 46! I knew that there was another name for Santa Claus but I don't think I've ever used "Father Christmas" myself... perhaps this shows how Americanized things are already. I didn't know what a "box car" or a "mother-in-law" (residence) were and probably wouldn't have called them a "goods van" or "granny flat" either...

I was mystified that there could even be another word for "baked potato"... I'd always thought that jacket potatoes were baked, thereby producing a baked potato. Shows what I know about potatoes. And napkin as "serviette"... well, perhaps, if you live in Kensington.