ochtach

Irish

From ocht (“eight”) +‎ -ach.

ochtach m (genitive singular ochtaigh, nominative plural ochtaigh)

(music) octave (an interval of twelve semitones spanning eight degrees of the diatonic scale, representing a doubling or halving in pitch frequency)

Declension of ochtach (first declension)

forms with the definite article
	singular	plural
nominative	an t-ochtach	na hochtaigh
genitive	an ochtaigh	na n-ochtach
dative	leis an ochtach don ochtach	leis na hochtaigh

From Middle Irish ochtach,^[2] from Proto-Celtic *ɸuxtākā,^[3] from Proto-Indo-European *pewḱ- (“pine”). Cognate with Ancient Greek πεύκη (peúkē, “pine”), Lithuanian puši̇̀s (“pine”), and German Fichte (“spruce”).

ochtach f (genitive singular ochtaí, nominative plural ochtacha) (literary)

Declension of ochtach (second declension)

bare forms
	singular	plural
nominative	ochtach	ochtacha
vocative	a ochtach	a ochtacha
genitive	ochtaí	ochtach
dative	ochtach ochtaigh (archaic, dialectal)	ochtacha

forms with the definite article
	singular	plural
nominative	an ochtach	na hochtacha
genitive	na hochtaí	na n-ochtach
dative	leis an ochtach leis an ochtaigh (archaic, dialectal) don ochtach don ochtaigh (archaic, dialectal)	leis na hochtacha

Mutated forms of *ochtach*
radical	eclipsis	with h-prothesis	with t-prothesis
ochtach	n-ochtach	hochtach	t-ochtach

Note: Certain mutated forms of some words can never occur in standard Modern Irish.
All possible mutated forms are displayed for convenience.

^ Quiggin, E. C. (1906), A Dialect of Donegal, Cambridge University Press, page 204
^ Gregory Toner, Sharon Arbuthnot, Máire Ní Mhaonaigh, Marie-Luise Theuerkauf, Dagmar Wodtko, editors (2019), “ochtach”, in eDIL: Electronic Dictionary of the Irish Language
^ Matasović, Ranko (2009), “*fuxtākā”, in Etymological Dictionary of Proto-Celtic (Leiden Indo-European Etymological Dictionary Series; 9), Leiden: Brill, →ISBN, page 144