The term for the maximum population size an environment can sustain is known as the carrying capacity. This concept is crucial in ecology, as it defines the limit of resources available in a given environment, such as food, water, and habitat space. When a population exceeds its carrying capacity, it can lead to resource depletion, increased competition, and potential population decline. Understanding carrying capacity is essential for managing wildlife, natural resources, and human populations, as it helps maintain ecological balance and sustainability.