Ummmmm, no.....you are eating sweet potatoes...
"Contrary to what even some grocery store produce guys think, yams and sweet potatoes are unrelated vegetables, though in both cases you're eating the root of a tropical vine. Sweet potatoes, Ipomoea batatas ("batata" is the original Taino name, whence potato), are an American plant of the morning glory family, whereas yams are of the genus Dioscorea. Yams, which are rarely seen in the U.S. and Canada but are a staple in tropical regions, can grow up to seven feet in length. The name is thought to derive from the West African word nyami, "to eat," which is heard in Jamaican patois expressions such as, Oonu wan fi nyam banana dem?, "Do you guys want to eat those bananas?" Some blame (or credit) yams for the high rate of twin births in certain parts of Africa."
Again, in the states, the words "yam" and "sweet potato" are used interchangeably, while not technically the same thing...