undercoat

under- +‎ coat

• Rhymes: -əʊt

undercoat (plural undercoats)

1. A layer of short hairs underneath the longer ones of an animal's fur
2. A coat of paint or other material applied onto a surface before that of a topcoat; a coloured primer.
   • 2022 November 30, David Staines, “The colourful Class 69s”, in RAIL, page 54:

     The conversion process is carried out by Progress Rail at Longport, from where they are dispatched in undercoat to Eastleigh for final painting.

3. (obsolete) A coat for wearing indoors, under an overcoat.

• overcoat, topcoat

undercoat (third-person singular simple present undercoats, present participle undercoating, simple past and past participle undercoated)

1. (transitive) To apply an undercoat to.

• read count, readcount