Temperature scale is a measure of how hot or cold something is. It is measured in different units, such as Kelvin (6 letters), Centigrade (10 letters), Rankine (7 letters), Fahrenheit (10 letters) and Celsius (7 letters). Kelvin is the base unit of temperature in the International System of Units (SI). Centigrade is another name for Celsius, which is used to measure temperatures in most parts of the world. Rankine is a temperature scale based on absolute zero, and is mainly used in engineering. Fahrenheit is a temperature scale used mainly in the United States, while Celsius is the most widely used temperature scale in the world.