Fun Fact: Centigrade vs. Celsius
The original temperature scale by Anders Celsius (1701-1744) was such that 0° was at the boiling point of water and 100° was at the freezing point of water. Yes, that's "backward." Upon his death — 2 years after defining this scale — it was flipped: 0° = freezing water and 100° = boiling water.
Since Celsius' scale was divided into 100, it is a centigrade scale. (Same reason why a centimeter is 1/100 of a meter.) Thus, any and all scales divided into 100 are centigrade scales and it is for this reason that usage of centigrade should not be used formally for degrees Celsius. In other words, you should always be using "degree Celsius."
Ultimately, the Celsius scale was redefined to be more exact in its definition. 0.1°C is defined to be the triple point of water (which is defined as exactly 273.16 K). And not just any water, but VSMOW that defines not just pure water but pure water by its isotopes of hydrogen and oxygen.
Recap:
0 K is defined as absolute zero
273.16 K and 0.1°C are defined as the triple point of water
100°C is defined as the boiling point of water under 101,325 Pa of air pressure
Note that 273.16 K and 0.1°C are the triple point, which means 0.0°C = 273.15 K.
This "awkward" definition of 273.16 K for the triple point is how 1 K = 1°C, and if, say, 100 K were defined as the freezing point of water then 1 K = 2.7315°C (not 2.7316°C). The definition of the unit Kelvin is not just a secondary effect of the definition points of the scales (it actually was for a while), but 1 K is exactly defined to be 1/273.16 of the triple point of water.