Opaca

Opaca is the feminine form of the Latin adjective opacus, meaning dark, shaded, or opaque. In taxonomy and biology, opaca is commonly used as a descriptive epithet in species names, serving as a morphological or color-related descriptor rather than indicating a taxonomic rank.

As a descriptive term, opaca conveys dullness, lack of gloss, or opacity in a surface or tissue. It is not itself a taxonomic category but a descriptive tool that appears across plant, fungal, and animal names to indicate appearance or texture.

In language and labeling, opaca appears in Romance languages such as Italian, Spanish, and Portuguese, where it translates to opaque and is used to describe materials or objects that do not transmit light. In English-language texts, the corresponding term is opaque or opacity; opaca may appear mainly in cross-language contexts or when discussing Latin names and their descriptive meanings.

See also: opacity, opacus, opaco.