Bay's home, standing firm (6)
I believe the answer is:
stable
I believe this clue is a double definition.
'bay's home' is the first definition.
(type of horse)
'standing firm' is the second definition.
(I've seen this before)
(Other definitions for stable that I've seen before include "Horse barn" , "It might accommodate Arab" , "Steady, enduring" , "Sure!" , "Firm - building for animals" .)