On the move, patrol entrance (6)
I believe the answer is:
portal
'entrance' is the definition.
(type of opening or entrance)
'on the move patrol' is the wordplay.
'on the move' indicates anagramming the letters.
'patrol' is an anagram of 'PORTAL'.
(Other definitions for portal that I've seen before include "Gate, entrance" , "'Doorway, entrance (6)'" , "Special website bringing together information from diverse sources in a uniform way" , "An imposing gateway" , "Grand and imposing entrance" .)