Dealing with, concerned with, or relating to the natural world and natural phenomena as objects of study or research. Now chiefly in natural knowledge…

Relating to the material universe or to natural science; physical. Sometimes: spec. of, relating to, or characteristic of the philosophers of the…

= physiological, adj. 1. Obsolete.

Of or relating to natural history.

Of or relating to natural science or a natural science.

Of or belonging to natural history; natural-historical.