—staple /ˈsteɪ.pl̩/
adjective [before noun]
► F0 basic or main; standard or regular: » The staple diet here is mutton, fish and boiled potatoes.» Prices of staple foods such as wheat and vegetables have also been increasing.» Her latest film is the staple offering of action and comedy that we have come to expect.Thesaurus+: ↑Standard and routinenoun [C] (BASIC)
► F0 a main product or part of something: » Shortages mean that even staples (= basic foods) like bread are difficult to find.» Phosphate has been a staple of this area for many years.» Romantic fiction and reference books are a staple of many public libraries.Thesaurus+: ↑Standard and routinenoun [C] (WIRE)
F0 a short, thin piece of wire used to fasten sheets of paper together. It has sharp ends that are pushed through the paper and then bent flat by a special device.
See picture: staples 
Thesaurus+: ↑Pins, clips, hooks and pegsThesaurus+: ↑Office equipment , ↑Communicating by telephone , ↑Paper and stationery
F0 a U-shaped piece of metal with sharp ends that is fixed into a surface to hold something, such as a wire fence, in a particular position
Thesaurus+: ↑Building materialsThesaurus+: ↑Pins, clips, hooks and pegsverb [T] ↑Verb Endings for staple
► F0 to fasten something using staples: » Would you mind stapling the reports together?Thesaurus+: ↑Office practices