10 across
Track
associated
with
12
down
9
(9)
Track associated with 12 down 9 (9)
hints
0
checks
0
hints
The definition is at the end of the clue.
How the clue works
The definition here is 9, a cross-reference to 9 across (RACE) — a greyhound being a racing dog. The wordplay builds it as a charade: GREY (a type of horse, cued by "12 down" which answers HORSE) followed by HOUND (meaning to track), giving GREYHOUND.