Catherine showed us the way on a road (6)
I believe the answer is:
howard
'catherine' is the definition.
(Catherine Howard was a wife of Henry VIII)
'the way on a road' is the wordplay.
'the way' becomes 'how' (how something is done).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'road' becomes 'rd' (abbreviation for road).
'how'+'a'+'rd'='HOWARD'
'showed us' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for howard that I've seen before include "See 6" , "See 7" , "Member of 7 [ORDER OF MERIT]" , "Castle - - , Yorks." , "T [Thespian]" .)