Bŭlb1, n.
n. [Fr. bulbe, Lat. bulbus, Gr. βολβός.]
Sense 1. (Bot.) A spheroidal body growing from a plant either above or below the ground (usually the latter), which is strictly a bud, consisting of a cluster of partially developed leaves, and producing, as it grows, a stem above, and roots below, as in the onion, tulip, &c. It differs from a tuber in not being solid.
Sense 2. (Anat.) A name given to certain parts which resemble in shape certain bulbous roots, as the bulb of the aorta.
Bulb of a tooth, the vascular and nervous papilla contained in the cavity of the tooth.—Bulb of the eye, the eye-ball.—Bulb, or root, of a hair, the part whence the hair originates. Dunglison.
Sense 3. An expansion or protuberance on a stem, as the bulb of a thermometer, which may be of any form, as spherical, cylindrical, curved, &c. Tomlinson.