Somewhere to graze all the horses in a race (5)
I believe the answer is:
field
'a race' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for field that I've seen before include "Area of farm land" , "See 11" , "Piece of land for crops, pasture etc" , "Area for crops/livestock" , "Flodden?" .)