cognatus

Cognatus is a Latin adjective and noun meaning “born of the same stock” or “related by birth.” It originates from con- “together” and gignere “to be born.” In Latin grammar, cognatus has gendered forms: cognatus (masculine), cognata (feminine), cognatum (neuter); and in the plural: cognati, cognatae, cognata.

In linguistics, cognatus yields the English term cognate, used to describe words or languages that share a common ancestor. Cognate words or cognate languages are related through a shared etymology, often illustrated by examples such as pater (Latin) and father (English), which reflect a common Indo-European origin.

In kinship and historical law, cognatus designates a blood relative. The term historically distinguished relatives by birth from those related by marriage (affines). In some legal contexts, cognati referred to persons connected by consanguinity within defined degrees.

In taxonomy and biological nomenclature, cognatus can appear as a Latin epithet in species names to indicate relatedness or similarity within a group. The exact sense depends on the taxon and the author describing the organism.

Cognatus also appears in scholarly discussions of kinship terminology, Latin prosody, and historical legal codes, where it helps distinguish blood ties from relationships established by marriage and clarifies the Latin roots of related English terms.