flashgun vs flash bulb

flashgun and flash bulb both are nouns.

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

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

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

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

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