Dear Geist,
Have you got a simple definition of the word irony? It seems one cannot say the word without three people each offering their notion of the real true correct meaning of the word.
—Unironic, Cyberspace
Dear Unironic,
To quote Daily Writing Tips, an excellent writers' website: “Irony usually signals a difference between the appearance of things and the reality.” Merriam-Webster sums up three kinds of irony.
Socratic irony: One person pretends ignorance and endlessly asks question after question of another, exposing that person's foolishness.
Deliberate use of words to express the opposite of the literal meaning, usually for humorous or sardonic effect.
Dramatic or tragic irony: Incongruity between the expected outcome and the actual one; or incongruity between a situation developed in drama, and the accompanying words or actions that are understood by the audience but not by the characters in the play.
The New York Times adds this caution: “A paradox, something that seems contradictory but may be true, is not an irony. Not every coincidence, curiosity, oddity and paradox is irony.”
—The Editors