From French carne 'corner,' via the printing term 'kern' for type that overhangs its body, extended to digital letter-spacing.
The adjustment of space between individual letter pairs in a typeface to achieve visually consistent spacing.
From 'kern,' the part of a metal type letter that overhangs its body, from French carne 'corner, projecting angle,' from Latin cardinem 'hinge.' In metal typesetting, a kern was the portion of a letter that extended beyond its block, allowing letters like A and V to nestle closer together. Key roots: *kard- (Proto-Indo-European: "to turn, pivot").
Bad kerning is so common and distracting that the internet coined the portmanteau 'keming'—which is what 'kerning' looks like when the r and n are spaced too closely and merge into an m.