A watt is a measurement of electricity, usually pertaining to light. Light bulbs luminosity is graded by wattage, such as a 60 watt bulb, 100 watt bulb and so on. You would find a watt in a light bulb, to start.

Yes, it will be perfectly safe.

In fact, Yes James Watt did invent the light bulb!

A 60 watt light bulb is a light bulb with 60 watts capacity. When talking about watts, you're talking about the power that is transferred from the appliance to the accessories. Therefore, the light bulb labeled "60 watts" takes 60 watts to light up. A 60 watt light bulb will not be as bright as a 120 watt light bulb.

A 15-watt fluorescent should produce about as much light as a 75-watt incandescent.