What is the definition of irony?

the expression of one's meaning by using language that normally signifies the opposite, typically for humorous or emphatic effect.

A contradiction between what the reader expects and what actually happens in a story. (APEX)

Explanation:

it was the battle of midway (june 4-7 1942), in which was an american decisive victory against the japanese navy. americans lost one aircraft carrier, one destroyer and 150 planes. japan lost 4 aircraft carriers, 1 heavy cruiser and 248 planes. american casualties were 307 and japanese casualties were 3057. japan never recovered from its loses and after midway the americans started getting the upper hand in the pacific war.