happening at a time subsequent to a reference time
"he apologized subsequently"
"he's going to the store but he'll be back here later"
"it didn't happen until afterward"
"two hours after that"
At a later or succeeding time.
"We finished our homework and then played outside afterwards."
In plain English: Afterwards means after something else has happened or finished.
"We ate dinner and then played cards afterwards."
Afterwards comes from the Old English word for "behind," which combined with a suffix to form an adverb meaning something that happened later in time. The modern spelling reflects how people naturally analyzed it as being made of the words "after" and "-wards."