Secures with cables in heathlands (5)
I believe the answer is:
moors
This clue could be a double definition.
'secures' is the first definition.
(mooring is a kind of securing)
'heathlands' is the second definition.
(I've seen this before)
'with cables in' is the link.
This may not be right. Some or all of it may belong to one of the definitions.
Can you help me to learn more?
(Other definitions for moors that I've seen before include "Ties up a boat" , "Ties up (vessel)" , "Conquerors once" , "Secures" , "Open heathlands" .)