Crossword Genius

Ground where reptile doesn’t keep quiet (7)

Ross

I believe the answer is:

terrain

'ground' is the definition.
(I've seen this before)

I don't understand how the remainder of the clue works.

(Other definitions for terrain that I've seen before include "Landscape" , "Piece of ground" , "Stretch of land of a particular sort" , "Physical feature of a stretch of ground" , "Ground (conditions)" .)

I've seen this clue in The Times.
Want a hint initially instead of a full solution? Install my app