The dictionary of the DigoPaul indicates that the adjective centigrade is used with reference to that linked to the centigrade scale. This scale, also called Celsius, has the melting point of ice as a value of 0 and the boiling point of water as a value of 100, always at normal pressure.

According to DigoPaul, a degree centigrade or degree Celsius is a unit that is used in these types of scales. Its symbol is ° C and it is used specifically as a unit of temperature (the physical quantity that reveals the level of heat).

As you can see, the notion of centigrade is associated with Anders Celsius, a Swedish scientist who was born in 1701 and died in 1744. Celsius proposed a centigrade scale of temperatures in which, as the heat increased, the degrees decreased. Simultaneously, when the heat was reduced, the degrees increased. Years later, Carlos von Linnaeus and Jean-Pierre Christin used the ideas developed by Celsius to create a similar scale, albeit inverted (degrees increase when the temperature rises and decrease when it falls).

At present, this centigrade scale whose degrees increase as the temperature rises is used in many countries to indicate the level of heat. That is why it is common to read or hear that there is a temperature of 5 degrees Celsius or 28 degrees Celsius, for example. According to the scale in question, 28 degrees Celsius refers to a temperature that registers a higher heat than 5 degrees Celsius.

It is important not to confuse this concept with that of the centesimal degree, a unit of measurement that is used as an alternative to the radian and the sexagesimal degree to work with plane angles. Also known as gon, gonio, and gradián. Its value is explained as the central angle with a length equal to 1/400 of a given circumference. Although gon is its international symbol, a lowercase letter g is often used at the end of the number in the superscript position.

Until 1948, the centesimal degree was also called the centigrade degree. However, the authorities of the International System of Units considered that it was necessary to find an alternative to reduce the chances of confusion and that is why they officially adopted the name degree Celsius.

Regarding the indiscriminate use of the terms centigrade and Celsius, it is necessary to mention that they are not synonymous in all cases, since there is at least one other centigrade scale with which confusion could be generated, that of Kelvin. The Kelvin scale is also based on a division into one hundred equal parts for the measurement of the boiling and freezing points of distilled water.

One of the differences between the kelvin and the Celsius degree is that the latter represents an accessory unit, that is, it is not the basic unit of the system, as is the case with the former. Today the definition of the degree Celsius starts from the kelvin and is expressed by means of the following equation: t (° C) = T (K) – 273.15. Any temperature interval has the same value in degrees Celsius and Kelvin.

Therefore, we know that these two units can be referred to as degrees centigrade by using as a reference a division into one hundred parts of the same magnitude. On the other hand, there is the degree Fahrenheit, a scale proposed in 1724 by the physicist and engineer Daniel Gabriel Fahrenheit for the measurement of temperature, according to which water freezes at 32 degrees and boils when it reaches 212.

For reference, let’s look at the conversion between these three units: the melting point of water at 1 atm of pressure is given 0 ° C, 32 ° F or 273.15 K; the boiling one, at 100 ° C, 212 ° F or 373.15 K. 