Means of moving from one floor to another (9)
I believe the answer is:
staircase
'means of moving from one floor to another' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for staircase that I've seen before include "Means of moving from one floor to another" , "It's Caesar (anag.)" , "A group of linked canal locks" , "Route between floors" , "Way between floors" .)