What does theta tell us?

Could you please explain what theta signifies in the context of our discussion? I'm particularly interested in understanding how it contributes to our understanding of the cryptocurrency market or financial analysis. Is theta a measure of volatility? Or does it have something to do with the rate of return? Could you also elaborate on how we can utilize theta in our financial decisions? I'm keen to gain a deeper insight into its significance and application. Thank you for your time and explanation.