1. 
2. 
[syn: Tuber, genus Tuber]
The Collaborative International Dictionary of English v.0.48:
Tuber \Tu"ber\, n.[L., a hump. knob; probably akin to tumere to
   swell. Cf. Tumid.]
   1. (Bot.)
      (a) A fleshy, rounded stem or root, usually containing
          starchy matter, as the potato or arrowroot; a
          thickened root-stock. See Illust. of Tuberous.
      (b) A genus of fungi. See Truffle.
          [1913 Webster]
   2. (Anat.) A tuberosity; a tubercle.
      [1913 Webster]
WordNet (r) 3.0 (2006):
tuber
    n 1: a fleshy underground stem or root serving for reproductive
         and food storage
    2: type genus of the Tuberaceae: fungi whose fruiting bodies are
       typically truffles [syn: Tuber, genus Tuber]