Yam (vegetable) Yam (vegetable) Yam is the common name for some plant species in the genus "Dioscorea" (family Dioscoreaceae) that form edible tubers. Yams are perennial herbaceous vines cultivated for the consumption of their starchy tubers in many temperate and tropical world regions. The tubers themselves are also called "yams", having numerous cultivars and related species. In parts of the United States and Canada, "yam" is sometimes used to refer to varieties of the unrelated sweet potato ("Ipomoea batatas"). The name, yam, appears to derive from Portuguese "inhame" or Canarian (Spain) "ñame", which derived from West African languages during trade. The main
Rooster tail the wake of objects within a flowing fluid. A fast current of water flowing over a rock near the surface of a stream or river can create a rooster tail—such commotion at the water's surface are avoided by boaters due to the near surface obstruction. Propellers on boats can produce a rooster tail of water in their wake, in the form of a fountain which shoots into the air behind the boat. The faster a boat goes, the larger the rooster tails become. The efficiency of a boat's hull design can be determined by the magnitude of the rooster tail—larger