Pickup truck by turret (5)
I believe the answer is:
tower
'turret' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for tower that I've seen before include "Stand very high (over)" , "Rise to great height" , "One drawing" , "famous prison" , "Turret" .)