mutual

Mutual is an English adjective and noun deriving from Latin mutuus meaning 'reciprocal.' In general use, it denotes a relation or arrangement that is shared or reciprocated by two or more parties, as in mutual interests, mutual respect, or mutual consent. As a noun, Mutual appears in the proper names of organizations or concepts.

In biology, the related term mutualism describes a symbiotic relationship in which all participating organisms benefit. Classic examples include pollinators such as bees and flowering plants, and the human gut microbiome, where species exchange energy or nutrients in ways that enhance survival for both sides.

In social and economic contexts, mutuality appears in concepts such as mutual aid, mutual societies, and mutual funds. Mutual aid refers to voluntary, reciprocal support within a community. Mutuals—including mutual insurance companies and mutual savings banks—are organizations owned by their members to provide insurance or financial services, rather than by external shareholders.

In law, mutual assent or mutual consent is the requirement that all parties agree to the same essential terms of a contract, creating a binding agreement.

The term is also used broadly in philosophy and ethics to describe reciprocity and shared benefit across individuals, groups, or species.