I don't know. But actually yeah, it seems like a lot of people use it the same way I do or misuse it the same way I do, or at least seem to understand me when I'm misusing it. My dictionary says irony means: "1. the use of words to express the opposite of what one really means 2. incongruity between the actual result of a sequence of events and the expected result". But I always think of it like almost the opposite of that meaning. Like when one thing happens or is going on/being talked about, and then another thing happens, etc that is like the first thing. Bad example: you're on the bus talking with a friend (or someone you just met on the bus, whatever) about a book you both loved as children. Then a child gets on the bus holding that book, anmd it's like, "oh wow, how ironic". I think I always say ironic when two things are not opposite or incongruous but when they're reflective, like one thing echoes the other, or one predicts or is an omen of the other or whatever.