how is celsius defined
adjective. noun. The definition of Celsius is something related a system of measuring temperature where water freezes at 0 degrees and boils at 100 degrees. A thermometer used to measure temperature and based on a scale where water boils at 100 degrees is an example of a Celsius thermometer.Celsius is defined as a system of measuring temperature where water freezes at 0 degrees and boils at 100 degrees.A temperature scale developed by Anders Celsius where water freezes at 0 degree is an example of Celsius. thermometer used to measure temperature and based on a scale where water boils at 100 degrees is an example of a Celsius thermometer. Celsius is defined as a system of measuring temperature where water freezes at 0 degrees and boils at 100 degrees.