Grain
The word grain has several meanings, most being descriptive of a small piece or particle.
Particle-related
The primary definition is the agricultural one, with the others derived from it.
- In agriculture, a grain is the seed of a grass, a simple dry fruit technically called a caryopsis. Such crops are often called cereals. Grain can also refer to other types of small seeds, though this is technically less correct.
- In units of measurement, the grain is a unit of mass, originally based on the weight of one grain of barley. One gram of metric weight equals 15.4323584 grains. It was used in the past for older drugs such as aspirin, for bullets, and for precious metals.
- In geology, a grain is a single particle of rock or other material, such as sand or salt; see grain size.
- In materials science (especially metallurgy), a grain is a single crystal inside solid-state matter, also referred to as crystallite — related to the obsolete term "corn" as in corned beef.
- In photography, the fineness of image resolution for photographic film (i.e., graininess of a picture), originally related to the (crystallographic) grain size of silver iodide.
Others
- In wood, grain describes the alignment and texture of the wood fibres. This is often important in its effect on woodworking techniques (e.g. going against the grain).
- In golf, the direction in which individual blades of grass lie, usually in reference to a putting green.
- In rocket science, grain refers to the solid propellant of a rocket (either solid fuelled or hybrid), more or less a hollow cylinder, sometimes textured inside, and possibly very large.
- Grain may refer to the place Isle of Grain in Kent, England, on which lies the village of Grain, Kent.
- Grain is one of the stocks in the game Stock Ticker.
- In music, see granular synthesis.