What is Clinch?

Clinch definition and meaning on Dictionary terms:
verb (used with object)

to settle (a matter) decisively: After they clinched the deal they went out to celebrate.
to secure (a nail, screw, etc.) in position by beating down the protruding point: He drove the nails through the board and clinched the points flat with a hammer.
to fasten (objects) together by nails, screws, etc., secured in this manner.
Nautical. to fasten by a clinch.