header, machine for harvesting grain, developed in the United States, Canada, and Australia; along with the binder, it was standard equipment for harvesting wheat in the United States and Canada until early in the 20th century, when the grain combine was widely adopted. The header clipped the heads of grain from the stalks and elevated them into a header barge, a wagon with one low side over which the cut material could be pitched out with forks onto a stack. Later in the autumn, the grain was threshed by a threshing machine.