A soliloquy is one variant of a monologue, which is a speech spoken by a single character. The soliloquy is spoken by the character alone on the stage, giving the impression of conveying an interior state, or sometimes in the presence of other characters but apparently not addressed to them.

Certain plays and characters, namely Hamlet, often match soliloquies with the character's personality. In King Lear, Shakespeare rarely does that.

Lear's "Blow, winds, and crack your cheeks!" monologue in Act III, Scene 2 is considered a soliloquy because he is not conversing with Fool. Rather, he is addressing the winds and other elements, and in many respects describing his interior state.

Here I stand, your slave—

A poor, infirm, weak, and despised old man.

Edmund's "Thou, nature" speech in Act I, Scene 2, with its concluding line, "Now, gods, stand up for bastards!" is another well known soliloquy.

While Goneril and Cordelia have monologues, those are not soliloquies.

There are not many soliloquies in King Lear. The best example of a soliloquy in this play is the opening speech by the villainous Edmund in Act II, scene 2, beginning with the words "Thou, nature, art my goddess; to thy law / My services are bound." Edmund is all alone and is expressing his thoughts aloud.

In the opening lines of Act IV, scene 1, Edgar is alone and speaking his thoughts aloud in a soliloquy of nine lines, beginning with "Yet better thus, and known to be contemn'd, / Than still contemn'd and flatter'd."

Lear's famous tirade in the opening of scene 2 of Act III may be considered a soliloquy even though he is accompanied by the Fool. He is not speaking to the Fool and is entirely unaware of his presence.