What's a Bathrobe ?
A bathrobe is a dressing gown made from towelling or other absorbent fabric and may be donned while the wearer's body is wet, serving both as a towel and a body covering when there is no immediate need to fully dress.
Source : Bathrobe Wikipedia
What's a Banyan ?
A banyan (through Portuguese banian and Arabic بنيان, banyān, from the Tamil "vaaniyan (வாணியன்)/ vanigan (வணிகன்)", the Gujarati વાણિયો, vāṇiyo, meaning "merchant", ) is a garment worn by European men and women in the late 17th and 18th century, influenced by the Japanese kimonos brought to Europe by the Dutch East India Company in the mid-17th century. Banyan is also commonly used in present-day Indian English and other countries in the Indian Subcontinent to mean "vest" ("undershirt" in American English, "singlet" in Australian English).
Also called a morning gown, robe de chambre or nightgown, the banyan was a loose, T-shaped gown or kimono-like garment, made of cotton, linen, or silk and worn at home as a sort of dressing gown or informal coat over the shirt and breeches. The typical banyan was cut en chemise, with the sleeves and body cut as one piece. It was usually paired with a soft, turban-like cap worn in place of the formal periwig. An alternative style of banyan was cut like a coat, fitted, with set-in sleeves, and was closed with buttons and buttonholes.
Source : Banyan Wikipedia