Is Wattmeter One Word or Two?

Wattmeter is a noun. A noun is a type of word the meaning of which determines reality.

What is wattmeter in English?

: an instrument for measuring electric power in watts.

How do you use a wattmeter?

A wattmeter is a tool used to measure the amount of electricity being used. The wattmeter measures the electricity used in terms of the number of watts used. To use it, plug it into an outlet, then plug in your electrical device into the wattmeter. It will measure the amount of electricity your device is using.