What is the meaning of staple?

noun

• Usually plural. ( a necessary commodity for which demand is constant)
  • synonyms: basic
• A natural fiber (raw cotton, wool, hemp, flax) that can be twisted to form yarn.
  • usage: "staple fibers vary widely in length"
  • synonyms: staple fiber, staple fibre
• Material suitable for manufacture or use or finishing.
  • synonyms: raw material
• 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.

verb

• Secure or fasten with a staple or staples.
  • usage: "staple the papers together"

adjective

• Necessary or important, especially regarding food or commodities.
  • usage: "wheat is a staple crop"