tánaise

Perhaps from to- +‎ ad- +‎ ne- + the root of saidid (“to sit”), from Proto-Celtic *sedeti, from Proto-Indo-European *sed-. A similar formation, prefixed with imm-, underlies imthánad (“alternation”).^[1]

• IPA^(key): /ˈtaːnisʲe/

tánaise

1. second
   • c. 845, St Gall Glosses on Priscian, published in Thesaurus Palaeohibernicus (reprinted 1975, Dublin Institute for Advanced Studies), edited and with translations by Whitley Stokes and John Strachan, vol. II, pp. 49–224, Sg. 159^a2

     Air in tan no·labrither in cétni persin ƚ in tánaisi do·adbit ainm hi suidiu.

     For when you say the first person or the second, you show a noun in this.

• Irish: tánaiste
  • → English: Tánaiste

• Gregory Toner, Sharon Arbuthnot, Máire Ní Mhaonaigh, Marie-Luise Theuerkauf, Dagmar Wodtko, editors (2019), “tánaise”, in eDIL: Electronic Dictionary of the Irish Language