Quiz: Remember the definition of mal de mer?
Middle English pilwe, from Old English pyle "pillow," from West Germanic *pulwi(n) (cf. Old Saxon puli, Middle Dutch polu, Dutch peluw, Old High German pfuliwi, German Pfühl), an early borrowing (2c. or 3c.) from Latin pulvinus "little cushion, small pillow," of uncertain origin. Modern spelling is from mid-15c. Pillow fight (n.) attested from 1837; slang pillow talk (n.) first recorded 1939.
1620s, from pillow (n.). Related: Pillowed; pillowing.