What does 'mean' mean?

As a noun in math, " mean " is one of several " averages ".

Answer: the mode, another average, is the most common number in a group.
Example group of numbers : 1, 2, 3, 3, 4, 5, 6, 7, 8, 9.
3 is the mode.


The " mean " is the half-way mark in a list of numbers when they are in numerical order.

It is easily found by adding all the numbers together and dividing by the total count,

as in :


1,2,3,4,5,6,7 - a very simple list of numbers


The mean is found to be :

28 ( the sum of all numbers ) / ( divided by ) 7 ( the total count of the numbers in the list ) = 4. [ The mean number of the whole list is 4. ]

In this very simple example, you can easily see that the mean is the exact middle number.

Most often, the mean is not clearly observed since the list is usually not in numerical order, and you must then calculate the value, as above, by summing all numbers and then dividing by the count.

In the very first example above, 10 numbers add up to 48. The mean of that list is 4.8 actually, but we see the number 5 is closest to the calculated mean, and thus we would use the number 5 as the mean of that list.

Try this idea on several of your own example lists and it will become very clear for you.
It means when you add up all the numbers and divide them by how many there are. It can also mean being aggressive or hurtful in a way, in a repeated manner, such as, "You're mean!" or "You don't need to mean about it!" It can also mean "be defined", as used in the question, so you could have said, "What is mean defined" or "How can mean be defined?"