Nuclear weapon (6,4)
There are a few possibilities for this:
atomic bomb
'nuclear weapon' is the definition.
(I know that H-bomb is a type of nuclear weapon)
This is the entire clue.
(Other definitions for h-bomb that I've seen before include "Nuclear weapon" , "Atomic weapon" , "Extremely powerful weapon" , "Explosive weapon" , "Hydrogen weapon" .)
'nuclear weapon' is the definition.
(A-bomb is an example)
This is all the clue.
(Other definitions for a-bomb that I've seen before include "Weapon of mass destruction" , "Killer" , "Nuclear weapon" , "deterrent" , "Atomic weapon" .)
'nuclear weapon' is the definition.
(atomic bomb is a kind of nuclear weapon)
This is all the clue.
(Another definition for atomic bomb that I've seen is " Nuclear weapon".)