The branch of knowledge that deals with the natural or physical world; a life science or physical science, such as biology, chemistry, physics, or…

= natural history, n.

Natural philosophy, natural science. Also: a particular system or doctrine of natural science. Obsolete.

Originally: †the branch of knowledge that dealt with all natural objects, animal, vegetable, and mineral (obsolete). Now: the study of animals and…

The study or pursuit of natural history. Frequently attributive. Obsolete.

The study of plants, animals, natural phenomena, etc., now usually as carried out by amateurs, or by younger children in schools; an instance of this.