Definition
Temperature unit
A temperature unit names the size of the steps used on a temperature scale.
What it means
A temperature reading needs a number and a unit, such as 20 °C or 68 °F. The unit tells how large each step is; the scale also decides where its number labels are placed. Kelvins and Celsius degrees have equal-sized steps, although their zero points differ.
Remember it
The scale is the number line; the unit is the size of one step.
Example
Water warms from 18 °C to 23 °C, a change of 5 °C. That same temperature interval is 5 K because one Celsius-degree interval and one kelvin interval have the same size.
Watch for
A temperature value and a temperature interval are different: 20 °C is a point on a scale, while a rise of 20 °C is a size of change.
Common mix-up
The SI unit name is kelvin and its symbol is K; it is not written “degree kelvin” or °K.
Exact meaning
A temperature unit is a unit used with a specified temperature scale to express a temperature value or a temperature difference.