Old IrishEdit


From cét- (first) +‎ aín (fasting), literally first fast.



cétaín f (genitive cétaíne)

  1. Wednesday
    • c. 800–825, Diarmait, Milan Glosses on the Psalms, published in Thesaurus Palaeohibernicus (reprinted 1987, Dublin Institute for Advanced Studies), edited and with translations by Whitley Stokes and John Strachan, vol. I, pp. 7–483, Ml. 113d3
      .i. dia cétaíne ro·gabad in salm-so.
      i.e. [it was] on a Wednesday that this psalm was sung.
    • Trecheng Breth Féne, published in The Triads of Ireland (1906, Dublin: Royal Irish Academy), edited and with translations by Kuno Meyer, §216
      Trí banláe: lúan, Máirt, cétain.
      Three woman-days: Monday, Tuesday, and Wednesday.


Feminine ī-stem
Singular Dual Plural
Nominative cétaínL cétaínL cétaíniH
Vocative cétaínL cétaínL cétaíniH
Accusative cétaínN cétaínL cétaíniH
Genitive cétaíneH cétaíneL cétaíneN
Dative cétaínL cétaínib cétaínib
Initial mutations of a following adjective:
  • H = triggers aspiration
  • L = triggers lenition
  • N = triggers nasalization


  • Middle Irish: cétaín


Old Irish mutation
Radical Lenition Nasalization
cétaín chétaín cétaín
pronounced with /ɡ(ʲ)-/
Note: Some of these forms may be hypothetical. Not every
possible mutated form of every word actually occurs.

See alsoEdit

Further readingEdit