Definition of "coating"

"Chocolate and cream," the standard colours of G.W.R. rolling stock for 21 years, are now being replaced by an all-over utility coating of reddish-brown. This is the third time that a uniform brown has been adopted as the standard livery of G.W.R. carriages.

1943 March and April, “G.W.R. Rolling Stock Colours”, in Railway Magazine, page 106

You can, if you like, give the completed cork wall a protective coating of sealer, stain, varnish, wax or polish, so you will be able to use liquid cleaners on it.

1980, Robert M. Jones, editor, Walls and Ceilings, Time-Life Books, page 48

The bogey gave him a right coating.

1931, The Police Journal, volume 4, page 501