What is a dynamic character? What is a static character? How are they different?

In a story, a dynamic character is someone who undergoes an important, internal change because of the action in the plot. Ebenezer Scrooge, from Charles Dickens's A Christmas Carol, is a classic example. When we first meet him, he is mean, bitter, and avaricious. Through his experiences with the three ghosts, he becomes generous, kind, and beloved.
A static character is one whose personality doesn't change throughout the events in the story's plot. Dickens, again, is the source of an example in Joe Gargery, from Great Expectations. Joe remains faithful, honorable, and loyal despite being robbed by a convict and treated poorly by his wife and nephew.