yam (Noun) — Edible tuber of any of several yams.
yam (Noun) — Any of a number of tropical vines of the genus Dioscorea many having edible tuberous roots.
yam (Noun) — Sweet potato with deep orange flesh that remains moist when baked.
yam (Noun) — Edible tuberous root of various yam plants of the genus Dioscorea grown in the tropics world-wide for food.