n. (Zool.) The larva of any geometrid moth. It progresses forward by first bringing the rear end of the body forward, forming a loop, then moving the front part of the body; called also measuring worm, measuringworm, spanner, and looper. See Geometrid. [ 1913 Webster ]
(n) small hairless caterpillar having legs on only its front and rear segments; mostly larvae of moths of the family Geometridae, Syn. inchworm, looper