terciáris

Terciáris is a Latin-derived adjective meaning tertiary or of the third order, used in various languages to describe a third level, stage, or category in scientific and academic contexts. It stems from Latin tertiarius, itself from tertius, meaning "third."

In geology, the historical term terciár or terciáris has been used for the geologic period that followed the Cretaceous. In modern geochronology, the period is subdivided into the Paleogene and Neogene, and the term Tertiary is now typically treated as an informal or historical label rather than a formal unit in many classifications.

In biology and chemistry, the adjective appears in terms such as tertiary structure of proteins and tertiary alcohols, describing features or compounds associated with a central atom bonded to three groups. In economics and sociology, tertiary refers to the service sector—activities that provide services rather than produce goods or extract resources. In linguistics, tertiary phenomena may be used to describe a third-level aspect of analysis, such as tertiary stress in phonology in some frameworks.

In Romanian and other languages, forms related to terciáris are used as masculine adjectives in technical terminology, with gendered forms adapting to the grammar of each language. The term thus functions as a cross-disciplinary label for concepts that are third in rank, level, or sequence, and it appears in both historical and contemporary contexts across disciplines.