A' The term A, as in Aristotle, can be represented by the crossword solution ALPHA, which is a five-letter word. Alpha is the first letter of the Greek alphabet and is often used to refer to something that is first or primary in a particular field or activity. In this case, it is used to refer to Aristotle, who was an ancient Greek philosopher and scientist who made significant contributions to many fields, including logic, metaphysics, mathematics, physics, biology, botany, ethics, politics, agriculture, medicine, theatre, and rhetoric.