The science of life; that branch of knowledge which treats of living matter as distinct from matter which is not living; the study of living tissue. It has to do with the origin, structure, development, function, and distribution of animals and plants.
- The science of life and of living organisms, including their structure, function, growth, origin, evolution, and distribution. It includes botany and zoology and all their subdivisions.
- The life processes or characteristic phenomena of a group or category of living organisms: the biology of viruses.
- The plant and animal life of a specific area or region.