1. a layer of short, dense fur beneath the longer outer fur of an animal
2. a coat of paint or primer applied before the final coat
3. a garment worn under another coat for warmth

1. to apply an undercoat of paint or primer to a surface

Examples

• The dog’s thick undercoat keeps it warm in winter.
• Golden retrievers shed their undercoat twice a year.
• Apply an undercoat before painting the walls.
• The primer serves as an undercoat for the final paint.
• She wore a wool undercoat beneath her winter jacket.
• Make sure to undercoat the metal before applying the topcoat.
• The painter will undercoat the surface tomorrow.