Respecting Church vessel for apse (6)
I believe the answer is:
recess
'apse' is the definition.
(I've seen this before)
'respecting church vessel' is the wordplay.
'respecting' becomes 're' (regarding).
'church' becomes 'CE' (abbreviation for Church of England).
'vessel' becomes 'SS' (prefix in ship names eg SS Great Britain).
're'+'ce'+'ss'='RECESS'
'for' is the link.
(Other definitions for recess that I've seen before include "Break from proceedings" , "Small niche or court holiday" , "Nook for a break from business" , "Politicians' holiday" , "Space sent in a wall" .)