the larva of a hawk moth, Manduca quinquemaculata, having a black, hornlike structure at the rear, that feeds on the leaves of tomato, potato, and other plants of the nightshade family.
Origin of tomato hornworm
First recorded in 1920–25
Also called potato worm.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019