Definition of roundtail in English:

roundtail

noun

  • A surfboard, snowboard, etc., with a rounded tail; the tail of such a board.

noun

  • 1US (more fully "roundtail chub") the cyprinid chub Gila robusta, found in certain rivers in western North America.

  • 2A domesticated variety of the guppy, Poecilia reticulata, having a rounded tail fin.

Origin

1960s; earliest use found in Surfer<br>early 19th century.