Cognate

In linguistics, cognates are words that have a common etymological origin.

The term derives from the Latin cognatus (blood relative). In linguistic research it is generally understood as excluding doublets and loan words, although broader definitions are used in other areas such as language teaching.

Characteristics of cognate words

Cognates do not need to have the same meaning, which may have changed as the languages developed separately. For example, consider English starve and Dutch sterven or German sterben ("to die"); these three words all derive from the same Proto-Germanic root, *sterbaną ("die"). English dish and German Tisch ("table"), with their flat surfaces, both come from Latin discus, but it would be a mistake to identify their later meanings as the same. Discus is from Greek δίσκος (from the verb δικεῖν "to throw"). A later and separate English reflex of discus, probably through medieval Latin desca, is desk (see OED s.v. desk).

Cognates also do not need to have obviously similar forms: e.g., English father, French père, and Armenian հայր (hayr) all descend directly from Proto-Indo-European *ph₂tḗr.