An environment is the set of conditions, entities, and relations that surround and affect a thing. Every thing exists within an environment: the soil chemistry around a plant, the social institutions shaping a person’s choices, the runtime context of a running program.
The concept is relational rather than absolute. An environment does not exist independently — it is always the environment of something. The same physical space constitutes different environments for different organisms: a forest canopy is the environment of an arboreal bird but not of a soil microbe, even though both occupy the same forest. What counts as “the environment” depends on which thing is under consideration and which relations matter for the question being asked.
In ecology, the environment of an organism includes abiotic factors (temperature, moisture, light, chemical composition) and biotic factors (other organisms that compete, cooperate, predate, or decompose). These factors interact: the shade cast by a tree canopy changes the light environment for understory plants, which in turn changes the nutrient environment for soil organisms.
The concept extends beyond ecology. In computing, an environment is the set of bindings (variables, functions, configurations) available to a running process. In social science, a person’s environment includes institutions, norms, economic conditions, and the built landscape. In each domain, the core idea is the same: the surrounding context that shapes what a thing can do and what happens to it.
From a relational perspective, the boundary between a thing and its environment is not fixed. The roots of a tree are part of the tree but also part of the soil environment for neighboring organisms. This permeability of boundaries is one reason the concept of environment resists sharp definition — it names a relation, not a substance.