1. A solid, liquid, or gaseous fuel that is obtained from biological raw material; the conversion is accomplished through thermochemical or biological methods.
2. Gas such as methane or liquid fuel such as ethanol (ethyl alcohol) made from organic waste material, usually by microbial action.
3. A renewable fuel, e.g., biodiesel, biogas, and methane, that is derived from biological matter.

1. A mixture of methane and carbon dioxide along with traces of other gases, such as nitrogen, hydrogen, and water vapor, that is produced during anaerobic digestion.
2. A combustible gas produced by microbial activity, usually referring to methane produced by microbial fermentation of organic wastes.

1. A term presented by Thomas Huxley to the principle that life originates from preexisting life only and never from nonliving material.
2. The principle that all living organisms have derived from previously existing living organisms not through spontaneous generation.

1. Produced by the activity of living organisms.
2. That part of biology that seeks to account for the resemblances and the differences in organisms related by descent. It is the science that simply studies in living organisms such genetic phenomena as heredity and evolution, development and variation; whereas the doctrinal movement that tries to anticipate or enforce the practical utilization of the scientific principles studied is eugenics.

Produced by a living organism or resulting from the actions of living organisms; necessary for life processes.

1. Originating from life or producing life.
2. Living on or in other organisms.

1. The branch of biochemistry that deals with the relation of chemicals found in the soil to living organisms; the biological application of geochemistry.
2. The study of the influence of living organisms and life processes on the chemical structure and history of the earth.
3. The study of interactions between the biosphere and its mineral environment, e.g., the study of the effect of living organisms on the weathering of rocks and of the concentration of elements by living systems.

1. The science of the geographical distribution of living things, animal (zoogeography) and vegetable (phytogeography).
2. The study of the geographical distributions of organisms, their habitats (ecological biogeography) and the historical and biological factors that produced them (historical biogeography).

A specialist in biogeography.

That part of the lithosphere within which living organisms can occur.

A sedimentary structure consisting of a fossilized remnant or mark formed in soft sediment by the movement of an animal and pressed in sedimentary rock.

A proposed general term for the “life-sciences”.

1. An instrument for analyzing and rendering visible the movements of animals; used in diagnosis of certain nervous diseases.
2. To make a biograph which is an earlier form of “cinematograph”.
3. To write or prepare a biography.

Of, relating to, or dealing with biography.

1. The history of the lives of individual men and women, as a branch of literature.
2. The written record of the life of an individual. 3. The life-course of a man or other living being; the “life-history” of an animal or plant.

That field of study dealing with the effect on living organisms (particularly man) of abnormal gravitational effects produced; that is, by acceleration or by free fall; in the former case, heavier than normal weight is induced, and in the latter weightlessness.