About time for pet (3)
I believe the answer is:
cat
'pet' is the definition.
(I have seen 'Common pet ' mean 'cat' so perhaps 'pet' could also mean 'cat')
'about time' is the wordplay.
'about' becomes 'ca' (abbreviation for 'circa'**).
'time' becomes 't'.
'ca'+'t'='CAT'
'for' is the link.
(Other definitions for cat that I've seen before include "Common pet" , "Moggy" , "Carnivore; whip" , "Tabby" , "Feline - whip" .)