sta·ple 2 
(stāpəl)
(stāpəl)n.
1. A thin piece of wire shaped as three sides of a square so that it can be driven into thin or soft material, such as paper, and bent to function as a fastener.
2. A similarly shaped piece of metal with pointed ends, driven into a surface to secure a bolt, hook, hasp, or length of wiring.
tr.v. sta·pled, sta·pling, sta·ples
To secure or fasten by means of a staple or staples.
[Middle English, from Old English stapol, post, pillar.]