The Collaborative International Dictionary of English v.0.48:

Bulbous \Bulb"ous\, a. [L. bulbosus: cf. F. bulbeux. See Bulb,
   n.]
   Having or containing bulbs, or a bulb; growing from bulbs;
   bulblike in shape or structure.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bulbous
    adj 1: shaped like a bulb [syn: bulblike, bulbous, bulb-
           shaped]
    2: curving outward [syn: bellied, bellying, bulbous,
       bulging, bulgy, protuberant]