What's the relevance of carriage? (7)
I believe the answer is:
bearing
I believe this is a double definition.
'what's the relevance' is the first definition.
(bearing is a kind of relevance)
'carriage?' is the second definition.
('bearing' can be a synonym of 'carriage')
'of' acts as a link.
(Other definitions for bearing that I've seen before include "Attitude - pivot - reference" , "Manner - pivot - reference" , "Deportment" , "Compass point" , "supplied by Air Traffic Control" .)