Other forms: evened up; evens up
To even up is to make something more balanced or equal. If you don't even up your little sisters' Halloween candy, making sure they have the same number of treats, you'll never hear the end of it!
You even up when you bring something unequal or uneven back into balance. If basketball scores even up in the second half, the teams are tied. And to even up everyone's soda, just pour a little more in the glass that came up short. Another way to even something up is to align it, the way you even up a stack of papers by tapping them on your desk, so the edges are lined up neatly.