staple

(usually plural) a necessary commodity for which demand is constant

a natural fiber (raw cotton, wool, hemp, flax) that can be twisted to form yarn; "staple fibers vary widely in length"

material suitable for manufacture or use or finishing

a short U-shaped wire nail for securing cables

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

secure or fasten with a staple or staples; "staple the papers together"

necessary or important, especially regarding food or commodities; "wheat is a staple crop"