The distinction between the Celsius and centigrade scales can seem confusing -- but the two terms refer to the same scale of measurement, and both use the same degree designation -- degrees C. The two scales -- Centigrade and Celsius -- originated in the 18th century, and were used interchangeably until the mid-20th century. Although some people might still use the term centigrade on occasion, the official term is Celsius.
The names Celsius and centigrade date back to the scale’s two originators. In 1742, Swedish scientist Anders Celsius designed a temperature scale that used 0 degrees as the boiling point of water and 100 degrees as the freezing point. One year later, French scientist Jean Pierre Cristin designed a similar temperature scale: Cristin's scale used the same divisions as Celsius's scale, but Cristin’s scale set the freezing point at 0 degrees and the boiling point at 100 degrees. Cristin called his scale the centigrade scale, because it was divided into 100 parts, with centi as the prefix for 100. The Celsius/centigrade scale in use today is Cristin's, but it was interchangeably referred to as either Celsius or centigrade in different regions of the world.
Official Adoption of Celsius
In 1948, 33 nations met for the 9th General Conference on Weights and Measures. This conference was a meeting of countries to determine the standards of measurement used in those countries -- these conferences were established in 1875 by a treaty known as the Convention of the Metre -- also known as the Treaty of the Meter. At the 1948 conference, the centigrade/Celsius scale was officially designated the Celsius scale in honor of Anders Celsius.