kern (n.)

1680s, "part of a metal type projecting beyond the body," as the head of an -f- or the tail of a -j-. According to Century Dictionary this is identical with kern "a grain" (see kernel), but OED says it is from French carne "projecting angle, quill of a pen" (12c.), Old North French form of Old French charne "hinge, pivot," from Latin cardinem "hinge." Related: Kerned "having the top or bottom projecting beyond the body;" kerning.