machine that harvests grain crops
A combine harvester, also called a combine, is a machine that harvests crops. Its name comes from doing three separate parts of harvesting crops at once:
- reaping: cutting and collecting crops when they are ready for harvesting,
- threshing: separating the parts of a crop that can be eaten by people from the parts that can't, and
- winnowing: removing the already separated parts of the crop that can't be eaten by people, the chaff, while keeping the part that can be eaten, the grain.
- Constable, George; Somerville, Bob (2003). A Century of Innovation: Twenty Engineering Achievements That Transformed Our Lives, Chapter 7, Agricultural Mechanization. Washington, DC: Joseph Henry Press. ISBN 0-309-08908-5.