Governed as certain lines may be (5)
I believe the answer is:
ruled
I believe this is a double definition.
'governed' is the first definition.
('rule' can be a synonym of 'govern')
'as certain lines may be' is the second definition.
(as in paper with ruled lines)
(Other definitions for ruled that I've seen before include "Exercised control over" , "(Of writing paper) having printed lines" , "Reigned or ordered" , "Governed - with lines" , "Were tops" .)