Definition of "Staple" :

noun: (usually in the plural) a necessary commodity for which demand is constant

noun: paper fastener consisting of a short length of U-shaped wire that can fasten papers together

noun: a short U-shaped wire nail for securing cables

noun: material suitable for manufacture or use or finishing

noun: a natural fiber (raw cotton, wool, hemp, flax) that can be twisted to form yarn

"Staple fibers vary widely in length."

verb: secure or fasten with a staple or staples

"Staple the papers together."

adjective: necessary or important, especially regarding food or commodities

"Wheat is a staple crop."