The unit of measure of an angle is degree.
A unit of measurement is a definite magnitude (number) of a quantity defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement.
For example, a length is a physical quantity. A metre is a unit of length that represents a definite predetermined length (which is 1 meter here). When we say 10 metres (or 10 m), we actually mean 10 times the definite predetermined length called "metre".
Similarly, Angles are also measured in some unit which is called a degree.
For example, 30∘ is said as 30 degrees.
Note:- is length always measured in meter? Which unit would you choose to measure the distance from Bangalore to Delhi? is there any other unit too to measure an angle?