(n.) A captain of a war vessel whose name appeared, or was "posted," in the seniority list of the British navy, as distinguished from a commander whose name was not so posted. The term was also used in the United States navy; but no such commission as post-captain was ever recognized in either service, and the term has fallen into disuse.
POST-CAPTAIN
Meaning of POST-CAPTAIN in English
Webster's English dictionary. Английский словарь Webster. 2012