mutually

Mutually is an adverb that denotes reciprocity: an action, condition, or relationship is shared or experienced by two or more parties in a way that each side is affected or engaged.

Etymology: The adverb is derived from the adjective mutual, which comes from Old French mutuel and Latin mutuus meaning borrowed or shared.

Common usages include phrases such as mutually beneficial, mutually agreed, and mutually exclusive. Generally, mutually describes effects produced in both directions, contrasting with unilateral actions.

In logic and probability, mutually exclusive events are events that cannot occur at the same time; the occurrence of one precludes the other.

Mutually also appears in phrases like mutually assured destruction and mutual aid, illustrating its role in expressing shared outcomes among actors.

Notes: Mutually describes reciprocity; the related adjective mutual describes a shared relationship. The two terms are related but used in different grammatical contexts: mutually modifies verbs or adjectives to emphasize reciprocity, while mutual describes the relationship itself.