sub-postmaster 
noun chiefly British
A man in charge of a sub-post office.Post bosses says they have agreed with the sub-postmaster at the Burnden Post Office in Manchester Road, Bolton, that it will shut its doors for the last time in July....
- The Government may be filling the Post Office's financial black hole but is not directly supporting the threatened businesses of sub-postmasters.
- The Post Office maintains that sub-postmasters are agents - but going ahead with the appeal would have cost the Post Office more money.