mean / average
media / promedio
the sum of the values divided by how many values there are.
Example
The mean of 4, 8, and 12 is \tfrac{4 + 8 + 12}{3} = 8.
In Spanish
media / promedio — la suma de los valores dividida entre la cantidad de valores.
La media de 4, 8 y 12 es \tfrac{4 + 8 + 12}{3} = 8.