IPA: /ˈbæθruːm/
KK: /ˈbæθrum/
A room in a house or building that has a toilet and often a sink and a shower or bathtub.
I need to go to the bathroom before we leave.
Bathroom → The word is formed from "bath" (from Old English *baþ*, meaning a washing or immersion) and "room" (from Old French *rom*, meaning a space or area). A bathroom is a room designated for bathing or washing.
Think of a 'washing area' ('bath') combined with a 'space' ('room') — that's what a bathroom is.