nonliving

Nonliving is a term used to describe entities that do not possess the properties typically associated with living organisms. In biology, life is commonly described through criteria such as organized structure, metabolism, growth, response to stimuli, reproduction, and adaptation. Because no single criterion universally defines life, the boundary between living and nonliving is not always clear, and some entities are subject to debate.

Nonliving things include minerals, rocks, water, air, soil, and manufactured objects such as tools and machines. They do not sustain metabolism or reproduce independently.

Borderline cases include viruses, viroids, and prions. Most definitions classify viruses as nonliving because they require host cells for replication and lack independent metabolism, though they can evolve and interact with hosts.

Organisms after death are considered nonliving. In science and education, distinguishing living from nonliving helps organize knowledge and methods. In astrobiology, life-detection efforts use criteria derived from biology to assess whether signals indicate living systems or abiotic processes. In ecology, nonliving components such as air, water, minerals, climate, and soil influence and constrain living organisms.