Small domestic animals brought up stairs (5)
I believe the answer is:
steps
'stairs' is the definition.
('step' can be a synonym of 'stair')
'small domestic animals brought up' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'domestic animals' becomes 'pets' (I've seen this before).
'brought up' is a reversal indicator (down clues only).
's'+'pets'='spets'
'spets' back-to-front is 'STEPS'.
(Other definitions for steps that I've seen before include "Measures taken" , "See 2" , "Stairs; paces" , "taken to get on" , "Paces; measures" .)