flashcard vs flash card

flashcard and flash card both are nouns.

Word	Noun	Adjective	Verb	Adverb
flashcard	Yes	No	No	No
flash card	Yes	No	No	No

As nouns, flashcard and flash card are synonyms defined as:

flashcard and flash card: a card with words or numbers or pictures that is flashed to a class by the teacher

flashcard (noun)	flash card (noun)
a card with words or numbers or pictures that is flashed to a class by the teacher	a card with words or numbers or pictures that is flashed to a class by the teacher