Webster's Revised Unabridged Dictionary · 1913

(Zoology) Pertaining or belonging to the Geometrida.

(Zoology) One of numerous genera and species of moths, of the family Geometrida; -- so called because their larva (called loopers, measuring worms, spanworms, and inchworms) creep in a looping manner, as if measuring. Many of the species are injurious to agriculture, as the cankerworms.