The Collaborative International Dictionary of English v.0.48:
Epiglottis \Ep`i*glot"tis\, n. [NL., fr. Gr. ?; 'epi` upon + ?, ?, tongue. See Glottis.] (Anat.) A cartilaginous lidlike appendage which closes the glottis while food or drink is passing while food or drink is passing through the pharynx. [1913 Webster]WordNet (r) 3.0 (2006):
epiglottis n 1: a flap of cartilage that covers the windpipe while swallowing