What is flat character and Round character?

Character may broadly be divided into two types- flat or static and round or dynamic. The flat and static character is rather static. Such a character remains essentially stable or unchanged in his or her outlook and disposition from the beginning to the end.  The round character, however, is one that changes, either gradually or radically,  with the progress of the action or theme of the story concerned.  Such a round character has an intrinsic development. 

A flat or static character,  also called a type or two dimensional character,  as implied, undergoes no change,  and sticks to some fixed ideas, notions or habits or manners all through. Such a character is built around a single quality idea or even mannerism,  and as such can be easily identified.  This is generally presented in certain external outlines and motives or motive, and without much detail to individualize . A flat or static character, in fact ,  can be fairly and adequately designated in a single phrase of sentence or from a single angle.

Miss Betsey in David Copperfield, Mrs. Bennett in Pride and Prejudice, Squire Western og Tom Jones are such characters.

A round or dynamic character is noy static, has no permanent habit, stead-fast mannerism nor any fixed viewpoint or prejudice. He or She revolves round no fixed, flat ground, but changes his or her course, grows mature and reveals his or her own trends of mind or traits of nature in course of time. There seems to be a curve towards the round on a plain surface, and this is the formation of the round character on the base, formed of more than one factor, 

Jane Austen's hero and heroine in Pride and Prejudice Darcy and Elizabeth respectively-are the quite satisfactory instances of round fictional characters. Becky Sharp of Thackeray's Varity Fair is a round character,  as her nature cannot be summed up in a single phrase. In fact,  her character has no single factor to show. Tolstoy's Anna Karenina and Flaubert's Emma Bovary are in the same standard, round characters. These characters cannot be denominated in a single formula. They are found to grow and change in a convincing way.