What is the definition of temperature and how is it measured in different systems?

Temperature is a measure of the average kinetic energy of particles in a substance. It can be measured using different systems, such as the Celsius scale, Fahrenheit scale, and Kelvin scale. The Celsius scale is based on the freezing and boiling points of water, with 0C as the freezing point and 100C as the boiling point. The Fahrenheit scale is commonly used in the United States and is based on the freezing and boiling points of water, with 32F as the freezing point and 212F as the boiling point. The Kelvin scale is based on absolute zero, the theoretical lowest possible temperature, with 0K as absolute zero.