Sequence of words for length of time (8)
I believe the answer is:
sentence
I believe this clue is a double definition.
'sequence of words' is the first definition.
(I've seen this before)
'length of time' is the second definition.
(time in prison)
'for' acts as a link.
(Other definitions for sentence that I've seen before include "Line of words" , "Part of a message" , "String of words satisfying grammatical rules" , "Judgment on convict" , "That which ends with a full stop" .)