Why is the ninth month called September?
"loose white robe," late 13c., from Old French surpeliz, from Medieval Latin superpellicium "a surplice," literally "an over fur garment," from Latin super "over" (see super-) + Medieval Latin pellicium "fur garment, tunic of skins," from Latin pellis "skin" (see film (n.)). So called because it was put on over fur garments worn by clergymen to keep warm in unheated medieval churches.
white outer vestment worn by clergymen, acolytes, choristers, or other participants in Roman Catholic and in Anglican, Lutheran, and other Protestant religious services. It is a loose garment, usually with full sleeves. Originally the surplice was full length, but gradually it was shortened to the knees or above. In the 20th century some surplices were again made full length