ATP in text and online slang stands for "Answer The Phone." It’s commonly used in messages when someone wants the recipient to pick up a call quickly. However, ATP means can also have other meanings also that is depending on the context, such as "At This Point" in conversations. In scientific terms, ATP refers to Adenosine Triphosphate, an essential energy-carrying molecule in cells. Always check the context in which ATP is used to make the correct meaning.