Who is Toto?

Toto may refer to many things but a popular reference is to a small dog in the movie The Wonderful Wizard of Oz (1900). Toto belongs to Dorothy Gale, the heroine, and plays a key role at several points in the movie including running away (which causes Dorothy to chase after him and get pulled into the story) and pulling the curtain back to reveal that the Wizard is just an old man.