cognate

Concise Oxford English Dictionary © 2008 Oxford University Press:
cognate /ˈkɒgneɪt/

▶adjective

• 1 Linguistics (of a word) having the same linguistic derivation as another (e.g. English father, German Vater, Latin pater).

• 2 formal related; connected.

  ■ related to or descended from a common ancestor.

  Compare with agnate.

▶noun

• 1 Linguistics a cognate word.

• 2 Law a blood relative, especially on the mother's side.

– derivatives
cognately adverb,
cognateness noun.

– origin C17: from L. cognatus, from co- ‘together with’ + natus ‘born’.