The missile from Uncle? (3)
I believe the answer is:
sam
This clue is a double definition.
'the missile' is the first definition.
(abbreviation for surface-to-air missile)
'uncle?' is the second definition.
(Uncle Sam is an example)
'from' is the link.
(Other definitions for sam that I've seen before include "together once" , "Uncle" , "Boy" , "Casablanca piano player" .)