See also: aeth and æð


Alternative formsEdit


From Proto-Brythonic *-aɨθ, from Insular Celtic *-axtā, suffixal use of Proto-Celtic *axtā. Cognate with Cornish -eth, Breton -ezh, Irish -acht, Scottish Gaelic -achd and Manx -aght.



-aeth f (plural -aethau)

  1. Forms abstract nouns.
    aelod (member) + ‎-aeth → ‎aelodaeth (membership)
    llofrudd (murderer) + ‎-aeth → ‎llofruddiaeth (murder)
    meddyg (doctor) + ‎-aeth → ‎meddygaeth (medicine)
    amau (to doubt) + ‎-aeth → ‎amheuaeth (doubt)
  2. territory controlled by, -ship, -age, -y, -dom
    ymherodr (emperor) + ‎-aeth → ‎ymerodraeth (empire)
    esgob (bishop) + ‎-aeth → ‎esgobaeth (diocese, bishopric)

Usage notesEdit

With names of leaders, -aeth can be both concrete and abstract, for instance iarllaeth (earldom) is both the rank of being an earl and the territory controlled by one.

Most nouns in -aeth are feminine. Common exceptions are gwasanaeth (service) and hiraeth (longing, homesickness).

Derived termsEdit


R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present) , “-aeth”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies