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.
"soft tissues of the mouth," Old English goma "palate, side of the mouth" (single or plural), from a Germanic source represented by Old Norse gomi "palate," Old High German goumo; related to Lithuanian gomurys "palate," and perhaps from PIE root *ghieh- "to yawn, gape, be wide open."
"split, cloven," late 14c., past-participle adjective from cleave (v.1)). Cleft palate attested from 1828.
"things dainty and gratifying to the palate," early 15c., plural of delicacy in the "fine food" sense.