cowl n.

"hood attached to a gown or robe, chiefly worn by monks and characteristic of their profession; a hooded garment," Middle English coule, from Old English cule, from earlier cugele, from Late Latin cuculla "monk's cowl," variant of Latin cucullus "hood, cowl," which is of uncertain origin. As "covering (originally cowl-shaped) for the top of a chimney or vent-pipe" by 1812. Hence cowling for "removable engine cover," 1917, originally in reference to aircraft.