Keep recovery vehicle (5)
I believe the answer is:
tower
This clue could be a double definition.
'keep' is the first definition.
(keep can mean a fortified structure)
'recovery vehicle' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for tower that I've seen before include "Tall structure" , "tug attached to wreck, for example" , "Tall column" , "famous prison" , "See 6 Down" .)