flashbulb vs flash bulb

flashbulb and flash bulb both are nouns.

Word	Noun	Adjective	Verb	Adverb
flashbulb	Yes	No	No	No
flash bulb	Yes	No	No	No

As nouns, flashbulb and flash bulb are synonyms defined as:

flashbulb and flash bulb: a lamp for providing momentary light to take a photograph

Other synonyms of flashbulb include flash, flash lamp, flashgun, photoflash.

flashbulb (noun)	flash bulb (noun)
a lamp for providing momentary light to take a photograph	a lamp for providing momentary light to take a photograph