noun
1. : a treatise on any aspect of natural history but especially on ecology
edited a natural history of spiders
2.
a. : the natural development of something (as of an organism or disease) over a period of time
increasing knowledge of the natural histories of tumors — H.S.N.Greene
b. : a chronicle of the natural development of something over a period of time usually presenting an assemblage of principal facts and characteristics
the plays are a shrewd natural history of … Bohemian New York — Francis Fergusson
3.
a. : a former branch of knowledge embracing the study, description, and classification of natural objects (as animals, plants, and minerals) and thus including the modern sciences of zoology, botany, and mineralogy in so far as they existed at that time
b. : a modern branch of inquiry usually restricted to a consideration of these subjects from an amateur or popular rather than a technical and professional point of view