What is theta also known as?

Could you please explain to me what theta is commonly referred to as in the realm of cryptocurrency and finance? I'm quite curious to know its alternative names or designations, as I believe it holds significant value and importance within this field. Would you be able to enlighten me on this matter, perhaps even provide some context or background information related to theta's nomenclature? I'm eager to broaden my understanding of this topic and appreciate your assistance in this endeavor.