fruit bat vs megabat

fruit bat and megabat both are nouns.

Word	Noun	Adjective	Verb	Adverb
fruit bat	Yes	No	No	No
megabat	Yes	No	No	No

As nouns, fruit bat and megabat are synonyms defined as:

fruit bat and megabat: large Old World bat of warm and tropical regions that feeds on fruit

fruit bat (noun)	megabat (noun)
large Old World bat of warm and tropical regions that feeds on fruit	large Old World bat of warm and tropical regions that feeds on fruit