cassock

noun3

1. •
   An item of clerical clothing: a long, sheath-like, close-fitting, ankle-length robe worn by clergy members of some Christian denominations.

   • When leading worship, Elsie usually wore a long black cassock and preaching bands. This would, of course, save her from the worry of choosing a suitable costume. — 2014
2. •
   (no longer used) A military cloak or long coat worn by soldiers or horsemen in the 16th and 17th centuries.
3. •
   (no longer used) A coarse, loose cloak or gown, worn by women, sailors, shepherds, countryfolk etc.