A parody is an imitation of a style in such a way as to make fun of it, to hold it up to ridicule. It is often done by using exaggeration; sometimes by applying the style to an incongruous subject, as when Milton's heroic and very grand way of writing is used to describe making a cup of tea.
There is also a verb, ‘to parody’, meaning ‘to imitate or mimic for humorous purposes’, as in ‘Pope’s The Rape of the Lock parodies the epic genre’.
Parody is found in all art forms, and also in real life. Politicians' styles of speaking, and teachers' mannerisms, are frequently parodied, the former by their opponents and the latter by their pupils. Do not confuse parody with pastiche.
N.B. In musicology the term parody is used in a different way: it is applied to any musical material which copies or imitates other material, whether or not there is a humorous intention on the part of the composer. For more see Parody in music.