Real Dictionary

varnish
singular noun: The varnish on an object is the hard, clear, shiny surface that it has when it has been painted with varnish.
variable noun: Varnish is an oily liquid which is painted onto wood or other material to give it a hard, clear, shiny surface.

varnish in American English
a preparation made of resinous substances dissolved in oil (oil varnish) or in alcohol, turpentine, etc. ( spirit varnish), used to give a hard, glossy surface to wood, metal, etc.
to cover with varnish; brush varnish on
noun: a preparation consisting of resinous matter, as copal or lac, dissolved in an oil (oil varnish) or in alcohol (spirit varnish) or other volatile liquid. When applied to the surface of wood, metal, etc., it dries and leaves a hard, more or less glossy, usu
transitive verb: to apply varnish to; coat or cover with varnish

varnish in British English
noun: a preparation consisting of a solvent, a drying oil, and usually resin, rubber, bitumen, etc, for application to a surface where it polymerizes to yield a hard glossy, usually transparent, coating