"Heishi" is a traditional American Indian name for discoidal shell beads that have been manufactured to have the same diameter, or tapering diameters. The name has been used for similarly-made beads of many materials. Turquoise heishi beads are the most-often-seen non-shell heishi, in a Native American context.
Other common bead trade spellings are Hishi, Heishe or Heshi.