circuit card vs circuit board

circuit card and circuit board both are nouns.

Word	Noun	Adjective	Verb	Adverb
circuit card	Yes	No	No	No
circuit board	Yes	No	No	No

As nouns, circuit card and circuit board are synonyms defined as:

circuit card and circuit board: a printed circuit that can be inserted into expansion slots in a computer to increase the computer's capabilities

Other synonyms of circuit card include add-in, board, card, plug-in.

circuit card (noun)	circuit board (noun)
a printed circuit that can be inserted into expansion slots in a computer to increase the computer's capabilities	a printed circuit that can be inserted into expansion slots in a computer to increase the computer's capabilities