[This is so exciting, Lois gets to educate a kid about the first love of her life!]

It's short for 'opposite the editorial page.' A lot of people get it wrong and think it means 'opinion-editorial.' Editorials are usually unsigned pieces from members of a paper's board of editors. On the page opposite are signed pieces by authors who aren't on the editorial board, and expressing opinions of their own.

That's where the term came from, anyway. It's a little different these days.