Temperature is a measure of the heat of an object. A hotter object has a higher temperature. A colder object has a lower temperature. An object's temperature depends on how fast the molecules within it are vibrating or moving. When an object is cooled the molecules slow down. For example, when water is cooled its molecules slow down and at 0 degrees Celsius, or 32 degrees Fahrenheit, it freezes into ice.
The theoretical temperature at which no further heat loss is possible, and at which all molecular movement would cease is called absolute zero. Absolute zero has never been achieved but is defined as -273 degrees Celsius or -459 degrees Fahrenheit or 0 degrees Kelvin. The very light gas Helium becomes a liquid at very close to absolute zero -270 degrees Celsius or -452 degrees Fahrenheit.