therefore vs hence

therefore and hence both are adverbs.

Word	Noun	Adjective	Verb	Adverb
therefore	No	No	No	Yes
hence	No	No	No	Yes

As adverbs, therefore and hence are synonyms defined as:

therefore and hence: (used to introduce a logical conclusion) from that fact or reason or as a result

Other synonyms of therefore include so, thence, thus.

therefore (adverb)	hence (adverb)
(used to introduce a logical conclusion) from that fact or reason or as a result	(used to introduce a logical conclusion) from that fact or reason or as a result
as a consequence	from this time
	from this place