Term, duration (6)
I believe the answer is:
period
I believe this clue is a double definition.
'term' is the first definition.
(a term is a period of time)
'duration' is the second definition.
(thesaurus)
(Other definitions for period that I've seen before include "Full stop or time interval" , "Era, epoch" , "Indefinite length of time" , "Stop in America" , "Stretch - cycle" .)