Source : Webster's Revised Unabridged Dictionary (1913)

Undercut \Un"der*cut`\, p.a.
   Cut away below.

Undercut \Un"der*cut`\, n.
   The lower or under side of a sirloin of beef; the fillet.

Undercut \Un`der*cut"\, v. t.
   To cut away, as the side of an object, so as to leave an
   overhanging portion.

Source : WordNet®

undercut
     n 1: the material removed by a cut made underneath
     2: the tender meat of the loin muscle on each side of the
        vertebral column [syn: {tenderloin}]
     3: a notch cut in the trunk of tree in order to determine the
        direction of its fall
     4: (sports) a stroke that puts reverse spin on the ball; "cuts
        do not bother a good tennis player" [syn: {cut}]
     5: a cut made underneath to remove material
     v 1: sell cheaper than one's competition [syn: {undersell}]
     2: cut away material from the underside of (an object) so as to
        leave an overhanging portion in relief
     3: cut away the underpart of; "undercut a vein of ore"
     4: strike (the ball) in golf, tennis, or hockey obliquely
        downward so as to give a backspin or elevation to the shot
     5: cut obliquely into (a tree) below the main cut and on the
        side toward which the tree will fall
     [also: {undercutting}]