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.
Parody can be applied to all art forms, and also to 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.