Flat character - A predictable character who has only one dominant characteristic
Flat characters are those that play a side role in the story, they do not change (or change too little) in the course of the narrative, they are simple, only exhibit one or two qualities, and do not show any emotional depth, thus, they tend to be very predictable.
Round character - A character who is complex in nature, with multiple aspects to his or her personality
A round character is the one that is the most similar to real humans being: they are complex, have multiple aspects or layers of personality, have depth in feelings and passions, have contradicting or inconsistent behaviors and they go through major changes throughout the story. This type of character is usually one of the main characters.
Dynamic character - a character who changes gradually during the course of the story
Dynamic characters are those that are not as complex as round characters but they do have experiences that lead them to gradually undergo changes or substantial transformation through the story, whether in personality, attitude, points of view or maturity; and these changes don't tend to be described outright, rather, these traits are referred to as they change over time.
Static character - A character who does not develop much during the story
Static characters are those that may have an interesting personality that attracts people's interest, and can also be protagonists, but that don't develop much (or nothing at all) during the story.
