Real Dictionary

irony
uncountable noun: Irony is a subtle form of humour which involves saying things that you do not mean.
variable noun: If you talk about the irony of a situation, you mean that it is odd or amusing because it involves a contrast.

irony in American English 1
a method of humorous or subtly sarcastic expression in which the intended meaning of the words is the direct opposite of their usual sense
noun: the use of words to convey a meaning that is the opposite of its literal meaning

irony in American English 2
of, like, or containing iron
adjective: consisting of, containing, or resembling iron

irony in British English 1
noun: the humorous or mildly sarcastic use of words to imply the opposite of what they normally mean

irony in British English 2
adjective: of, resembling, or containing iron