1. the lower or bottom parts of something, especially the belly and lower body of an animal
Usage: usually plural

Examples

• The robin has a red breast and pale underparts.
• The cat’s underparts were white while its back was black.
• Bird watchers often identify species by examining their underparts.
• The deer’s underparts were lighter in color than its sides.
• The fish had silver underparts that gleamed in the water.
• Many animals have lighter-colored underparts for camouflage.