"ornamental covering," c. 1300, houce "covering for the back and flanks of a horse," from Old French houce "mantle, horse-blanket" (Modern French housse), from Medieval Latin hultia "protective covering," from a Germanic source, from Proto-Germanic *hulfti (cognates: Middle Dutch hulfte "pocket for bow and arrow," Middle High German hulft "covering"), from PIE root *kel- (2) "to cover, conceal" (see cell). Sense of "case or enclosure for machine or part" is first recorded 1882.