Don't let go in the storage compartment (4)
I believe the answer is:
hold
'compartment' is the definition.
(thesaurus)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for hold that I've seen before include "Nelson?" , "Contain" , "Keep; part of ship" , "Ship's storage space" , "Continue" .)