As Mulligan affirms soon after calling down the stairs for "Kinch," he is the source of this nickname for Stephen: “my name for you is the best: Kinch, the knife-blade.” Ellmann says that Oliver Gogarty gave the name to Joyce and remarks that it imitated “the cutting sound of a knife” (131). This seems pretty obscure, but Mulligan's explanation certainly justifies hearing some sort of association with knives in the word. Other meanings of "kinch" may be worth exploring, not as alternatives but as complements.

JH 2020

Spear-pointed knife-blade, photographed by Mendaliv in 2007. Source: Wikimedia Commons.

Watercolor illustration of Fagin ca. 1889 by "Kyd." Source: Wikimedia Commons.

Source: John Hunt.