A grain is a small, hard, dry seed – with or without an attached hull or fruit layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes.

What is grain in science definition?

By The Editors of Encyclopaedia Britannica | View Edit History. grain, in metallurgy, any of the crystallites (small crystals or grains) of varying, randomly distributed, small sizes that compose a solid metal. Randomly oriented, the grains contact each other at surfaces called grain boundaries.

How is a grain defined?

A grain is a small, hard, dry seed - with or without an attached hull or fruit layer - harvested for human or animal consumption. A grain crop is a grain-producing plant. ... Thus, major global commodity markets exist for maize, rice, soybeans, wheat and other grains but not for tubers, vegetables, or other crops.