clevis

noun

Etymology: First attested in the 1590s. Ultimately related to cleave. Exact origin unknown; probably derived from the verb cleave. If so, the word ultimately may stem from Scandinavian: compare Old Norse kljúfa (“to split”), Old Norse klofi (“a forked stick”).

1. A U-shaped coupling having holes at each end, through which a bolt is run; used especially to fit attachments to a tractor or other vehicle as it allows a degree of rotation about the bolt.