Series ender, often (3)
I believe the answer is:
etc
'series ender often' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for etc that I've seen before include "'And the rest, in short (3)'" , "Etcetera (abbrev.)" , "And so on, in brief" , "And so forth (abbr)" , "And so on, briefly" .)