TUBER

n. bulb, short and round stem that is usually underground (Botany); rounded protuberance (Anatomy); one who deals with tubes

Tubers are different types of modified plant structures that are enlarged to store nutrients. They are used by plants to overwinter and regrow the next year and to reproduce. Three different groups of tubers are: potato tubers, stem tubers, and root tubers.
See more at Wikipedia.org...

Tuber /tu·ber/ pl. tu´bera, tubers [L.] 1. a swelling or protuberance. 2. the essential lesion of tuberous sclerosis, presenting as a pale, firm, [more]Tuber - Community and Resources

Noun
1. type genus of the Tuberaceae: fungi whose fruiting bodies are typically truffles
(synonym) genus Tuber
(hypernym) fungus genus
(member-holonym) Tuberaceae, family Tuberaceae
(member-meronym) truffle, earthnut, earth-ball

Noun
1. a fleshy underground stem or root serving for reproductive and food storage
(hypernym) stalk, stem
(hyponym) water chestnut

(n.)
A tuberosity; a tubercle.
  

(n.)
A genus of fungi. See Truffle.
  

(n.)
A fleshy, rounded stem or root, usually containing starchy matter, as the potato or arrowroot; a thickened root-stock. See Illust. of Tuberous.