Coincidence vs. Irony

COINCIDENCE

A reasonable concurrence of events or circumstances not having apparent causal connection with each other.

A Basic EXAMPLE: Rain on your wedding day (You may not have “wanted” rain, but bad weather is an expected, reasonable occurrence; unless of course, you are a weather forecaster and you predicted clear skies).

IRONY

Reference to something unreasonably happening or spoken or an unreasonable situation where the underlying meaning is the exact opposite of the literal meaning. 

A Basic EXAMPLE: A fire engine catching fire. (You certainly never expect a fire engine, a machine designed to extinguish fires, to be consumed by a roaring blaze; an unexpected, unreasonable occurrence.)

Basically, “coincidence” occurs when a possible, reasonable expectation of occurrence exists; “irony” occurs when an impossible, unreasonable expectation of occurrence exists.

OTHER EXAMPLES:

A health fanatic, who exercises and eats well, gets hit by a bus and dies.

Coincidence.

A health fanatic, who exercises and eats healthy, dies from excessive weight loss and food poisoning.

Irony.