dissimilitude

Dissimilitude denotes the quality or state of being dissimilar or unlike; the lack of similarity between two or more things. It is used across disciplines to discuss how closely a subject resembles or diverges from another, from a norm, or from an expected model. The term is from Latin dissimilitudo, from dissimilis “not like.”

In aesthetics and literary criticism, dissimilitude is often contrasted with resemblance. Some theories hold that art need not reproduce exact likeness; instead it may employ dissimilitude to emphasize particular features, convey interpretive meaning, or create stylistic effects. Critics may analyze how a portrait, scene, or narrative departs from ordinary life, highlighting differences that carry implication or mood.

In science and data analysis, dissimilarity is used more formally. In biology, it describes differences among organisms or structures. In statistics and machine learning, dissimilarity (or distance) metrics quantify how unlike two observations are, forming the basis for clustering, classification, or dimensionality reduction.

The concept is related to, but distinct from, difference, contrast, and similarity. It can function as a descriptive term about perception or as a methodological notion in measurement and analysis.

See also: similarity, distance, dissimilarity measures, representation, mimesis.