The term "aposematism" is commonly used as a synonym for warning coloration (i.e., something that is aposematic is warningly colored). The word literally means "away signal." Aposematism is the combination of a conspicuous signal and an unprofitable trait in a prey species.

Conspicuous signals are most often bright colors presented in banded or contrasting patterns. The banding pattern of coral snakes or the contrasting colors of Heliconius butterflies are obvious examples. These signals are easily seen over large distances. Auditory signals are also used. For example, some arctiid moths emit ultrasonic clicks upon approach of a bat predator. Rattlesnakes, with their caudal rattle, warn of their venomous bite.

The rattle of the rattlesnake is an aposematic signal that warns its predators of its venom.

Unprofitable traits include anything that harms the predator...