notion

A concept is a fundamental unit of cognition that classifies entities and encodes shared features. Concepts make it possible to form and combine ideas, draw inferences, and refer to external objects. They act as the meanings of words and play a central role in many cognitive processes, including perception, memory, and reasoning. Researchers distinguish different types of concepts based on their internal structure, mode of acquisition, and domain. These include simple and complex concepts, learned and innate concepts, concrete and abstract concepts, and natural and logical concepts.