This is a fine example of Stack* giving huge rankings to very bad answers. Big O is about execution time not complexity. (And describing execution time as "time complexity" as some comments do is ridiculous. A lot of something is not more complicated than a little of something. 4 isn't more complex than π -- and no, I'm not saying the reverse is true either.)
A plain English explanation of Big O notation shouldn't take more than a few sentences. It's not that complicated, especially if you don't get into nitty gritty.
A plain English explanation of Big O notation shouldn't take more than a few sentences. It's not that complicated, especially if you don't get into nitty gritty.