indistinguishably

Indistinguishably is an adverb that describes an action or comparison performed in a way that cannot be distinguished from another under the relevant criteria. It indicates that differences between objects, observations, or outcomes are not detectable within the given limits of perception, measurement, or analysis. The term is formed from the adjective indistinguishable with the suffix -ly.

Usage of indistinguishably spans everyday language and technical discourse. In ordinary speech, it can express extreme similarity, as in references to clothing, features, or behavior that make two things appear the same. In scientific and mathematical contexts, it is used to describe data, distributions, or results that are effectively the same within a specified tolerance or experimental error. In philosophy and theoretical discussions, it can characterize equivalence relations or classifications where distinctions are deemed irrelevant for a particular purpose.

Examples include: "The two samples behaved indistinguishably under all tested conditions," and "The rivals won indistinguishably many matches, making them hard to separate in standings." In discussions of perception, one might note that colors or sounds are indistinguishably similar to the observer within the device’s resolution.

See also: indistinguishable, indistinguishability, similarity.