noun: A tune that keeps replaying in one's head or that one keeps thinking about, especially if unwanted.
noun: (archaic) An earwig (“insect of the order Dermaptera”).
noun: (originally US) Short for corn earworm (“larva of the moths Helicoverpa zea (syn. Heliothis zea) and Helicoverpa armigera, which are agricultural pests”). [The large striped yellow-headed larva of the moths Helicoverpa zea (syn. Heliothis zea) and Helicoverpa armigera, especially destructive to corn, tomatoes, tobacco, and cotton bolls.]