The description of living beings—the “ornements” of the earth in all their diversity—is a central task of Jean Corbechon's fourteenth-century encyclopedia, the Livre des propriétés des choses, a translation into French of Bartholomaeus Anglicus's thirteenth-century De proprietatibus rerum, undertaken for Charles V of France. This article surveys the system for conceptualizing nature in Corbechon's encyclopedia. The Livre's account of animal, vegetable, and mineral life surpasses that of bestiaries and other vernacular encyclopedias, providing an idiom in French for the expression of natural diversity, complemented by new visualizations in the illustrated manuscripts. The concept of propriétés articulates the principles of diversity from elemental commonalities, through groups and subgroups such as birds and birds of prey, down to individual species. The Livre encourages the formation of analogies between beings, especially in terms of anatomy and modes of motion, reproduction, combat, and nutrition. Visual tools, including image grids, express groupings, and the etymologies of beings’ names gloss their properties and create links to human life. Ultimately, a restless ontological complexity of beings emerges, as the properties of animals, plants, and stones are enmeshed with each other and with human beings.