A long, close-fitting, ankle-length garment of the cleric that buttons down in front and is often tied at the waist with a cincture. Ordinary clerics (not hardline clerics) wear a black cassock, bishops a purple one, and cardinals red. Only the Pope wears a white cassock. It is worn by the clergy of certain churches usu during service and under vestments and by choiristers under a surplice or cotta.