The Collaborative International Dictionary
Dropworm
Dropworm \Drop"worm`\ (dr[o^]p"w[^u]rm`), n. (Zo["o]l.) The larva of any geometrid moth, which drops from trees by means of a thread of silk, as the cankerworm or inchworm. See inchworm and geometrid.
Wiktionary
dropworm
n. The larva of any geometrid moth, which drops from trees by means of a thread of silk, such as the cankerworm.