Patch of germicidal mat I annexed for dog (9)
I believe the answer is:
dalmatian
'for dog' is the definition.
(dalmatian is a kind of dog)
'patch of germicidal mat i annexed' is the wordplay.
'DALMATIAN' is hidden in amongst the letters.
However, I'm uncertain how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for dalmatian that I've seen before include "Man from coastal region" , "White-coated large dog with spots" , "animal spotted" , "Dog (from Croatia?)" , "Spotty breed of dog" .)