bulb

Any solid object rounded at one end and tapering on the other, possibly attached to a larger object at the tapered end.

“the bulb of the aorta”

A light bulb.

The bulb-shaped root portion of a plant such as a tulip, from which the rest of the plant may be regrown.

A bulbous protuberance at the forefoot of certain vessels to reduce turbulence.

The medulla oblongata.

To take the shape of a bulb; to swell.