noun
cassock
KAS-uk/ˈkæsək/
A long, close-fitting robe worn by clergy or choir members.
The priest’s black cassock reaches his ankles.

Etymology
The ancestor meant “long coat,” and English first used the word for a long gown or outer cloak. Its application to clergy's clothing developed from this broader garment sense.
In context
Sometimes altar servers or other ministers will wear a long black robe called a cassock, under a white, loose linen garment called a surplice.
More examples
- A white garment covered the priest’s cassock.
- The long cassock reached his ankles.
- She repaired a loose button on the cassock.
Forms
cassock · cassocks