Ever see someone talking to himself while on a stage? That's what you call a soliloquy — a character's speech voicing his or her own thoughts as if to himself. Shakespeare's plays are full of soliloquies.
The noun, soliloquy, comes from the Latin roots, solus "alone" plus loqui "speak" meaning "a talking to oneself." A soliloquy is a speech a character gives of his thoughts and reflections. Some of the most famous lines in drama are taken from soliloquies. Take "to be or not to be..." and "Tomorrow, and tomorrow, and tomorrow, Creeps in this petty pace..." as two examples of lines from soliloquies that have tortured high school students around the globe. Not the Globe Theater, Silly.