This document discusses definitions of learning from various authors. It begins by introducing learning as an important mental function for humans, animals, and artificial systems that relies on acquiring knowledge from perceived information. The document then presents two concepts of learning: a change in knowledge and behavior, and permanent changes in behavior, thinking, and feeling. It proceeds to provide definitions of learning from authors such as Munn, Skinner, Thorpe, Kimble, Gates, and Ambrose, emphasizing learning as an adaptive change in behavior resulting from experience and practice. The document concludes that learning is natural and occurs through an individual's environment, experiences, and interactions, resulting in a change in their behavior.