Arithmetic Mean
Determined by the sum of all values divided by the number of values.

Geometric Mean
Determined by the nth root (where n is the number of values) of the product of all values.

Median
Determined by the value (or arithmetic mean of 2 values) in the center of all values in ascending/descending order.

Mid-range
Determined by the arithmetic mean of the minimum and maximum values.

Mode
The most frequently occurring value.

https://en.wikipedia.org/wiki/Average#Summary_of_types