Other forms: bathrobes
A bathrobe is the long soft gown you pull on after a bath or a shower. Thick towelling, a belt tied at the waist, hanging on the back of the bathroom door.
A hotel leaves one folded on the bed or hanging beside the shower, and it is the same garment with a better label. British English says dressing gown more often, and a dressing gown gets worn round the house all morning, not only after washing. Americans say bathrobe, or shorten it to robe. The material tells you which kind you have: heavy white towelling for after the bath, thin cotton or silk for lounging about. It has no buttons and no zip — you wrap it round yourself and tie the belt.
1nounbathrobeA long, loose, soft gown worn after a bath or shower, or around the house.
“He answered the door in a bathrobe and one slipper.”
synonyms: dressing gown, robe
bathrobe is a garment.
Also accepted in games: robe, dressing gown
No mystery here: bathrobe is bath and robe pushed together, and the word says what it is for. The plain word robe still does the same job on its own, which is why an American will hand you 'a robe' and mean this exact thing.
From bath + robe.
Etymology from Wiktionary, CC BY-SA