Clevis \Clev"is\, n. [Cf. Cleave to adhere, Clavel.]

A piece of metal bent in the form of an oxbow, with the two ends perforated to receive a pin, used on the end of the tongue of a plow, wagen, etc., to attach it to a draft chain, whiffletree, etc.; -- called also clavel, clevy.

Source: Webster's Revised Unabridged Dictionary (1913)