afterwards vs afterward

afterwards and afterward both are adverbs.

Word	Noun	Adjective	Verb	Adverb
afterwards	No	No	No	Yes
afterward	No	No	No	Yes

As adverbs, afterwards and afterward are synonyms defined as:

afterwards and afterward: happening at a time subsequent to a reference time

Other synonyms of afterwards include after, later, later on, subsequently.

afterwards (adverb)	afterward (adverb)
happening at a time subsequent to a reference time	happening at a time subsequent to a reference time