-iaeth

Welsh

Etymology

From Proto-Brythonic *-aɨθ, from Insular Celtic *-axtā, suffixal use of Proto-Celtic *axtā. Cognate with Cornish -ieth.

Pronunciation

(North Wales, standard, colloquial) IPA^(key): /jaɨ̯θ/
- (North Wales, colloquial) IPA^(key): /jɛθ/, /jaθ/
(South Wales, standard) IPA^(key): /jai̯θ/
- (South Wales, colloquial) IPA^(key): /jɛθ/

Suffix

-iaeth f (noun-forming suffix, plural -iaethau)

alternative form of -aeth:
1. forms abstract nouns
  ‎arwr (“hero”) + ‎-iaeth → ‎arwriaeth (“heroism”)
  
  ‎deintydd (“dentist”) + ‎-iaeth → ‎deintyddiaeth (“dentistry”)
  
  ‎cydnabod (“recognise, acknowledge”) + ‎-iaeth → ‎cydnabyddiaeth (“recognition, acknowledgement”)
  
  ‎trin (“to treat”) + ‎-iaeth → ‎triniaeth (“treatment”)
2. forms nouns indicating the territory controlled by a specific officeholder; -ship, -age, -y, -dom
  ‎barwn (“baron”) + ‎-iaeth → ‎barwniaeth (“baronage, barony”)

Usage notes

With names of leaders, -iaeth can be both concrete and abstract, for instance barwniaeth (“baronage, barony”) is both the rank of being a baron and the territory controlled by one.

Most nouns in -iaeth are feminine. Common exceptions are gwahaniaeth (“difference”) and lluniaeth (“refreshments”).

Derived terms

Welsh terms suffixed with -iaeth

References

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