[bulb] n [L bulbus, fr. Gk bolbos bulbous plant] (ca. 1601) 1 a: a resting stage of a plant (as the lily, onion, hyacinth, or tulip) that is usu. formed underground and consists of a short stem base bearing one or more buds enclosed in overlapping membranous or fleshy leaves b: a fleshy structure (as a tuber or corm) resembling a bulb in appearance c: a plant having or developing from a bulb
2: a bulb-shaped part; specif: a glass envelope enclosing the light source of an electric lamp or such an envelope together with the light source it encloses
3: a rounded or swollen anatomical structure
4: a camera setting that indicates that the shutter can be opened by pressing on the release and closed by ending the pressure -- bulbed adj