What is "copper-belly"

Copperhead \Cop"per*head`\, n. [From its color.]

1. (Zo["o]l.) A poisonous American serpent ( Ancistrodon conotortrix), closely allied to the rattlesnake, but without rattles; -- called also copper-belly, and red viper.

2. A nickname applied to a person in the Northern States who sympathized with the South during the Civil War. [U.S.]