yam Meaning, Definition & Usage

  1. noun edible tuber of any of several yams
  2. noun any of a number of tropical vines of the genus Dioscorea many having edible tuberous roots
    yam plant.
  3. noun sweet potato with deep orange flesh that remains moist when baked
  4. noun edible tuberous root of various yam plants of the genus Dioscorea grown in the tropics world-wide for food

WordNet

Yam noun
Etymology
Pg. inhame, probably from some native name.
Definitions
  1. (Bot.) A large, esculent, farinaceous tuber of various climbing plants of the genus Dioscorea; also, the plants themselves. Mostly natives of warm climates. The plants have netted-veined, petioled leaves, and pods with three broad wings. The commonest species is D. sativa, but several others are cultivated.

Webster 1913