The term 'Pizza UNIT' is composed of two words: 'PIE' and 'UNIT'. PIE is a three-letter word that refers to a type of pastry dish that is usually filled with fruit, custard, or other sweet ingredients. UNIT is a four-letter word that refers to a single thing, person, or group that is part of a larger whole. Together, the two words form the term 'Pizza UNIT', which is used to refer to a single UNIT of pizza, such as a slice or a box.