Small crucifix over more than one entrance (5)
I believe the answer is:
doors
'more than one entrance' is the definition.
(door is a kind of entrance)
'small crucifix over' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'crucifix' becomes 'rood' ('rood' can be a synonym of 'crucifix').
'over' says the letters should be written in reverse.
's'+'rood'='srood'
'srood' backwards is 'DOORS'.
(Other definitions for doors that I've seen before include "Openings" , "Barriers to entrances" , "Entrance barriers" , "Swinging or sliding barriers" , "Portals" .)