Portraying in a critical or facetious way a real individual or group, or a figure representing a social, political, ethnic, or racial type. The effect is usually achieved through distortion or exaggeration of characteristics. (Genre Terms: A Thesaurus for Use in Rare Book and Special Collections Cataloguing, 2d ed)
Images used to comment on such things as contemporary events, social habits, or political trends; usually executed in a broad or abbreviated manner.
The faculty of expressing the amusing, clever, or comical or the keen perception and cleverly apt expression of connections between ideas that awaken amusement and pleasure. (From Random House Unabridged Dictionary, 2d ed)