Four words have been given, out of which three are alike in some manner and one is different. Select the odd one.

Axe Microscope Gun Amplify

Amplify

Except option 4 ,all are tools or instrument Axe - This tool is used to shape, split and cut wood Microscope - an instrument to see distant objects or small objects Gun - it is a ranged tool Amplify - to increase the strength of sound by using electrical equipment