separately vs singly

separately and singly both are adverbs.

Word	Noun	Adjective	Verb	Adverb
separately	No	No	No	Yes
singly	No	No	No	Yes

As adverbs, separately and singly are synonyms defined as:

Other synonyms of separately include individually, on an individual basis, one by one, severally.

separately (adverb)	singly (adverb)
apart from others	one by one; one at a time
	apart from others