Question

what does the word missile mean?
a weapon that is sent in the direction of its target
a weapon that is operated in a close range
a weapon that is used to break down a locked door
a weapon that tracks and follows the heat of its target

Explanation:

A missile is a weapon designed to be sent towards a target. "A weapon that is sent in the direction of its target" directly aligns with the basic definition of a missile. "A weapon that is operated in a close range" is more like a description of some short - range weapons like knives (in a combat sense) rather than a missile. "A weapon that is used to break down a locked door" is more of a tool like a battering ram. "A weapon that tracks and follows the heat of its target" is a specific type of missile (heat - seeking missile), but the general definition of missile is about being sent towards a target, not just heat - seeking.

Answer:

a weapon that is sent in the direction of its target