Definitions of yam:

• noun:   edible tuberous root of various yam plants of the genus Dioscorea grown in the tropics world-wide for food
• noun:   sweet potato with deep orange flesh that remains moist when baked
• noun:   any of a number of tropical vines of the genus Dioscorea many having edible tuberous roots
• noun:   edible tuber of any of several yams
• name:  A surname (very rare: popularity rank in the U.S.: #38788)