You dumbasses...

[Donger]

Originally Posted by milkman

Explain to me how it's wrong.

Here is what you wrote:

"By it's definition"

As you posted above, "it's" is correct when used as a contraction of "it is" or "it has."

Therefore, for what you wrote above to be correct, you must think that the non-contracted sentence would have been "By it is definition," which is obviously incorrect. Therefore, what you wrote above is incorrect.