Looking for the meaning or definition of the word postern? Here's what it means.
Noun
A backgate, back door, side entrance, or other gateway distinct from the main entrance.
(archaic) By extension, a separate or hidden way in or out of a place, situation etc.
(historical, military) A subterraneanpassage communicating between the parade and the main ditch, or between the ditches and the interior of the outworks.