Main Entry: bulb

Pronunciation: \ˈbəlb\

Function: noun

1 : a rounded dilation or expansion of something cylindrical <the bulb of a thermometer> ; especially : a rounded or pear-shaped enlargement on a small base <the bulb of an eyedropper>
2 : a rounded part: as a : a rounded enlargement of one end of a part—see bulb of the penis, bulb of the vestibule, end bulb, hair bulb, olfactory bulb b : medulla oblongata ; broadly : the hindbrain exclusive of the cerebellum c : a thick-walled muscular enlargement of the pharynx of certain nematode worms