What term describes a dramatic speech that reveals a character's inner thoughts while alone on stage?

The term that describes a dramatic speech revealing a character's inner thoughts while alone on stage is a soliloquy. In literature, especially in plays, a soliloquy allows characters to express their emotions and thoughts directly to the audience, providing insight into their motivations and dilemmas. This device is often used to create a deeper connection between the audience and the character, making them privy to the character's private reflections that would not be shared in the presence of others.

A monologue, although similar, usually refers to a lengthy speech by one character that may be directed to other characters as well, rather than expressing the character’s private thoughts in solitude. Dialogue consists of conversations between characters, which does not serve the same purpose as a soliloquy. An aside is a comment made by a character that is intended to be heard by the audience but not by other characters on stage, which differs from a soliloquy in that the character may not be entirely alone or fully expressing their thoughts in a reflective manner.