A reaper is a farm implement or person that reaps crops at harvest when they are ripe. Usually the crop involved is a cereal grass. The first documented reaping machines were Gallic reapers that were used in Roman times in what would become modern-day France. The Gallic reaper involved a comb which collected the heads, with an operator knocking the grain into a box for later threshing.

Agricultural machinery relates to the mechanical structures and devices used in farming or other agriculture. There are many types of such equipment, from hand tools and power tools to tractors and the countless kinds of farm implements that they tow or operate. Diverse arrays of equipment are used in both organic and nonorganic farming. Especially since the advent of mechanised agriculture, agricultural machinery is an indispensable part of how the world is fed. Agricultural machinery can be regarded as part of wider agricultural automation technologies, which includes the more advanced digital equipment and robotics. While agricultural robots have the potential to automate the three key steps involved in any agricultural operation, conventional motorized machinery is used principally to automate only the performing step where diagnosis and decision-making are conducted by humans based on observations and experience.