late 14c., "roof of the mouth of a human or animal; the parts which separate the oral from the nasal cavity," from Old French palat and directly from Latin palatum "roof of the mouth," also "a vault," which is perhaps of Etruscan origin [Klein], but de Vaan suggests an IE root meaning "flat, broad, wide." It was popularly considered to be the seat of the sense of taste, hence transferred meaning "sense of taste" (late 14c.), which also was in classical Latin.