A Watt (wattage) is a unit of measurement for power.  An electricity meter can only handle a set amount of wattage, so calculate your grow room’s power use before using it. You don’t want to use more than your network can handle.

More on electricity:

• Electrical Safety Guide For Growing Marijuana Indoors
• Growing Marijuana Safely

More electrical definitions and uses:

Power consumption | Power capacity | Electricity cables | Fuse | Grounding electricity | Transformer | Relay | Ballast |