kern
In typography and computing, the part of a letter that extends beyond its bounding box, or the adjustment of spacing between specific character pairs.
Adjusting the font's kerns makes the spacing between characters look natural.
In this typeface, a kern is set between 'A' and 'V'.
カーニング is the more common loanword for the process of kerning, while 左右突出部 is a technical Japanese term for the kern itself or the protruding part.
Compound of 左右 (left and right) + 突出部 (protruding part), describing the part of a glyph that extends sideways.