The term 'Abstract Unit of Exchange' is a three-letter acronym, TAT. It stands for 'Time, Attention, and Talent, ' which are the three main components of any exchange of goods or services. Time, Attention, and Talent are all intangible resources that can be exchanged for tangible goods or services. This type of exchange is often used in the modern economy, where people trade their skills and knowledge for money or other goods.