cornice vs valance board

cornice and valance board both are nouns.

Word	Noun	Adjective	Verb	Adverb
cornice	Yes	No	Yes	No
valance board	Yes	No	No	No

As nouns, cornice and valance board are synonyms defined as:

cornice and valance board: a decorative framework to conceal curtain fixtures at the top of a window casing

Other synonyms of cornice include pelmet, valance.

cornice (noun)	valance board (noun)
the topmost projecting part of an entablature	a decorative framework to conceal curtain fixtures at the top of a window casing
a molding at the corner between the ceiling and the top of a wall
a decorative framework to conceal curtain fixtures at the top of a window casing

cornice (verb)	valance board (verb)
furnish with a cornice