My unabridged dictionary defines irony as of 1933.

1. The word 'ironic' does not occur. Closest is 'ironical.'

2. There are three definitions. The first is ancient Greek and is too much trouble.

3. The second is for gentle sarcasm. In true irony, the meaning is the opposite of the words, but the statement is light. True sarcasm is 'bitter and reproachful.'

4. Third definition is that irony is when results are the opposite of expectation. The Frank Warren example upthread, where a gunshot leads to removal of a tumor and saves his life, fits this definition.

I believe I understand irony after all these years.