A watt is a unit of power that measures the rate at which energy is used or produced. It is defined as one joule per second and is commonly used to quantify electrical power. For example, a light bulb rated at 60 watts consumes 60 joules of energy every second it is on. In electrical systems, watts can be calculated by multiplying voltage (volts) by current (amperes). This relationship is important for understanding how much energy devices like appliances and computers consume. Higher wattage typically indicates more energy usage, which can affect electricity bills and energy efficiency.