saíthar

Old Irish

From Proto-Celtic *saitrom, from Proto-Indo-European *sh₂ey-tro-m, from *sh₂ey- (“to bind, fetter”) +‎ *-trom.[1]

saíthar n (genitive saíthir, nominative plural saíthra)

work, labour
- c. 800, Würzburg Glosses on the Pauline Epistles, published in Thesaurus Palaeohibernicus (reprinted 1987, Dublin Institute for Advanced Studies), edited and with translations by Whitley Stokes and John Strachan, vol. I, pp. 499–712, Wb. 10^c21
  Ba torad sa⟨í⟩thir dúun in chrud so ce du·melmis cech túari et ce du·gnemmis a ndu·gníat ar céli, act ní bad nertad na mbráithre et frescsiu fochricce as móo.
  It would be a fruit of labor for us in this way if we consumed every food and if we did what our fellows do, but it would not be a strengthening of the brothers and a hope of a greater reward.

Neuter o-stem
	Singular	Dual	Plural
Nominative	saíthar^N, saíthor	saíthar^N, saíthor	saíthar^L, saíthra
Vocative	saíthar^N, saíthor	saíthar^N, saíthor	saíthar^L, saíthra
Accusative	saíthar^N, saíthor	saíthar^N, saíthor	saíthar^L, saíthra
Genitive	saíthair^L, saíthir	saíthar, saíthor	saíthar^N, saíthor
Dative	saíthur^L	saíthraib	saíthraib
Initial mutations of a following adjective: ^H = triggers aspiration ^L = triggers lenition ^N = triggers nasalization

Old Irish mutation
Radical	Lenition	Nasalization
saíthar	ṡaíthar	unchanged
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.

Matasović, Ranko (2009) “*saytro-”, in Etymological Dictionary of Proto-Celtic (Leiden Indo-European Etymological Dictionary Series; 9), Leiden: Brill, →ISBN, page 325