Appendix:Irish third-declension nouns

The Irish third declension is made up of both masculine and feminine nouns; however, certain suffixes tend to have the same gender. The nominative singular can end in slender or broad consonants.

The third declension is characterised by the genitive singular having a broad consonant (depalatised if necessary) + a.

The dative singular is the same as the nominative singular.

The third declension plurals are strong plurals with very few exceptions.

The vocative forms, both singular and plural, are the same as the nominative.

Typical SuffixesEdit

Monosyllabic nouns of the third declension end in a wide range of broad and slender consonants, e.g., droim m, fuil f, gleann m.

There are many polysyllabic nouns with typical third declension suffixes. Many are used to create verbal nouns, which are in the third declension when substantive, e.g., tógáil f, imirt f, cailliúint f. Others are used to create: agent nouns, e.g., bádóir m, cuiditheoir m, siúinéir m; and abstract nouns, e.g., cumhacht f, eolaíocht f.

The suffix list highlights the gender associated with each.

Genitive FormationEdit

The third declension genitive singular is characterised by ending with a broad consonant plus ‑a:

The final consonant of slender radicals is broadened:

For the suffix ‑íl, an o is inserted to preserve broadness:

For the suffix ‑úint, the final t is dropped:

For the suffix ‑irt, the final t is lenited:

Weak PluralsEdit

A weak plural is characterised by the genitive plural having the same form as the nominative singular. There are very few [2] nouns classed as such in the third declension. The genitive singular and nominative plural of all of these nouns end in ‑a.

  • as m (time), gs. -a, npl. -a (lit.)
  • béas m (habit), -a, -a
  • crios m (belt), creasa, creasa (also strong)
  • dath m (colour), -a, -a (also strong)
  • deasghnáth m (rite), -a, -a
  • dol m (loop), -a, -a
  • dreach m (appearance), -a, -a (also as "front (lit.)", 2nd)
  • dreas m (duration), -a, -a
  • dún m (fort), -a, -a (also 1st, strong)
  • fuath m (shape), -a, -a (also strong)
  • mionn m (oath), -a, -aí (note plural)
  • ros m (wooded headland), -a, -a (also as "linseed", 1st weak)
  • tráth m (period), -a, -a (also strong)
  • tréad m (flock), -a, -a
  • treas m (file), -a, -a
  • ur m (border), -a, -a (lit.)
  • smacht m (control), -a, -a

Bare-form declension tableEdit

béas m (habit) Singular Plural
Nominative béas béasa
Vocative a bhéas a bhéasa
Genitive béasa béas
Dative béas béasa

Strong PluralsEdit

A strong plural is characterised by the genitive plural maintaining the same form as the nominative plural. Strong plural forms found in the third declension are:

  • ‑aí, ‑í
    • monosyllabic nouns (but not verbal nouns) in ‑áil: dáil f, dál
    • suffixes ‑éir, ‑óir, ‑úir: bádóir, bádóirí
    • suffixes ‑áint, ‑úint: leanúint, leanúintí
    • suffixes ‑acht: eolaíocht, eolaíocht
  • ‑ta, ‑te
    • monosyllabic nouns ending with ‑n: gleann m, gleanta; bliain f, blianta; móin f, móinte
  • ‑anna, ‑eanna
    • monosyllabic nouns: am m, amanna
  • ‑acha
    • verbal nouns as substansive in ‑áil: tógáil f, tógálacha
    • other examples: Samhain f, Samhnacha (with syncopation)
  • ‑a:
    • not to be confused with weak plural endings
    • flaith m , flatha
    • fuil f, fola
    • muir f, mara

Bare-form declension tablesEdit

Monosyllablic, slender consonant

droim m (back) Singular Plural
Nominative droim dromanna
Vocative a dhroim a dhromanna
Genitive droma dromanna
Dative droim dromanna

Monosyllablic, -an

gleann m (glen) Singular Plural
Nominative gleann gleannta
Vocative a ghleann a ghleannta
Genitive gleanna gleannta
Dative gleann gleannta

Suffix -óir

bádóir m (boatman) Singular Plural
Nominative bádóir bádóirí
Vocative a bhádóir a bhádóirí
Genitive bádóra bádóirí
Dative bádóir bádóirí

Polysyllabic nounsEdit

The majority of third declension nouns are polysyllabic, ending in the "typical suffixes" listed above, and whose gender and plural are easily predicted:

  • -éir, -óir, -úir: masculine; ‑í (slender)
  • -áil, -íl for verbal nouns as substantive: feminine; + acha (broadened)
  • -acht, -úint -irt: feminine; ‑í (slender)

For the remaining polysyllabic, there are some patterns:

  • -ain: bliain, Samhain

Monosyllabic nounsEdit

There is a realtively small set[3] of monosyllabic nouns in the third declension, having a wide range of consonant endings.

There are some patterns of note:

  • roots in -i(o)-
    • usually changing to -ea- in the genitive singular (more sledom in plurals)
    • mostly masculine
  • ending in -th
    • mostly masculine
  • ending in broad -ch(t)
    • mostly masculine
  • others to be sorted
  • Substantive (as opposed to verbal) nouns in ‑acht and ‑áil may be masculine or feminine, or belong to different declensions altogether.

Roots in -i(o)-Edit

  • bior m (spike), beara, -anna
  • bith m (world), beatha
  • bleacht m (milk), -a (originally bliocht)
  • briocht m (charm), breachta, -aí
  • cion m (love), -a, -ta
  • cith m (shower), ceatha, ceathanna
  • crios m (belt), creasa, -anna (also weak form)
  • fios m (knowledge), feasa-
  • leann m (ale), -a, -ta (originally lionn)
  • lionn m (humour (corp.)), leanna, -ta
  • lios m (ring-fort), leasa, -anna
  • liost m (teasal), -a, -anna
  • mil f (honey), meala
  • riocht m (shape), -a, -aí
  • sioc f (ice), seaca
  • siorc m (shark), -a, -anna (gs not with -ea-)
  • sliocht m (track), sleachta, sleachta (strong plural)
  • slios m (side), sleasa, sleasa (strong plural)

Ending in broad -thEdit

  • áth m (ford), -a, -anna
  • bláth m (flower), -a, -anna
  • both f (hut), -a, -anna
  • bruth m (heat), -a, -anna
  • cath m (battle), -a, -anna
  • cruth m (shape), -a, -anna
  • dath m (colour), -a, -anna
  • fáth m (cause), -a, -anna
  • guth m (voice), -a, -anna
  • rath m (favour), -a
  • ráth m (fort), -a, -anna (as f, "shoal"; as weak, "guarantor")
  • scáth m (shadow), -a, -anna
  • scoth m (flower), -a, -anna
  • snáth m (thread), -a
  • sruth m (stream), -a, -anna
  • tráth m (period), -a, -anna (weak version also)

Ending in broad -ch(t)Edit

  • acht m (act; doubt), -a, -anna
  • beacht m (exact measure), -a
  • brach m (pus), -a
  • ceacht m (lesson), -a, -anna
  • créacht f (wound), -a, -aí
  • deacht m (dictum), -a, -anna
  • dleacht f (due), -a, -anna
  • dreach m (appearance), -a, -a (weak)
  • dréacht m (draft), -a, -aí
  • éacht m (slaughter), -a, -aí
  • feacht m (current), -a, -aí
  • fuacht m (cold), -a
  • leacht m (grave), -a, -anna
  • léacht f (lecture), -a, -aí
  • loch m (lake), -a, -anna
  • locht m (fault), -a, -anna
  • luach m (value), -a, -anna
  • lucht m (charge), -a, -anna
  • neacht f (niece), -a, -anna
  • ócht f (virginity), -a
  • reacht m (law), -a, -anna
  • slacht m (neatness), -a
  • smacht m (control), -a, -a (weak plural)
  • trácht m (traffic), -a

Others to be sortedEdit

  • ab m (abbot), -a, -aí
  • am m (time), -a, -anna
  • aos m (people), -a
  • béas m (habit), -a, -a (weak)
  • cac m (shit), -a, -anna
  • Cáisc f (Easter), Cásca
  • cead m (permission), -a, -anna
  • cíos m (rent), -a, -anna
  • cleas m (trick), -a, -anna (also 1st)
  • cnámh m (bone), -a, -a (also 2nd)
  • cóir f (justice), córa, córacha
  • corcair m (purple dye), corcra
  • creamh m (wild garlic), -a
  • cuid f (part), coda, codanna
  • dáil m (meeting), dála, dálaí
  • dair f (oak), dara, daracha (also 5th)
  • deoin f (consent), deona, deonta
  • dream m (tribe), -a, -anna
  • droim m, droma, dromanna
  • dún m (fort), -a, -a (weak; also 1st, strong)
  • eang f (track), -a, -aí
  • eas m (waterfall), -a, -anna (as weak "stoat")
  • feadh m (extent), -a
  • feag f (rush), -a, -acha
  • feoil f (meat), feola, feolta
  • fíon m (wine), -a, -ta
  • flaith m (prince), flatha, flatha
  • fuath m (shape), -a, -a (weak and strong forms)
  • fuil f (blood), fola, fola
  • gean m (love), -a
  • gleann m (valley), -a, -ta
  • greim m (grip), greama, greamanna
  • leas m (benefit), -a
  • lus m (herb), -a, -anna
  • meas m (opinion), -a
  • meath m (decay), -a
  • modh m (manner), -a, -anna
  • móin f (turf), móna, -te
  • muir f (sea), mara, mara
  • nóin f (noon), nóna, nónta
  • rámh m (oar), -a, -aí (also 4th as rámha)
  • rang m (class), -a, -anna
  • ros m (wooded headland), -a, -a (weak)
  • rud m (thing), -a, -aí
  • scread f (scream), -a, -anna
  • snag m (gasp), -a, -anna
  • snas m (polish), -a, -anna
  • sos m (rest), -a, -anna
  • srón f (nose), -a, -anna (also 2nd)
  • táin f (plunder), tána, -te
  • taom m (paroxysm), -a, -anna (variant: tom)
  • tart m (thirst), -a
  • teas m (heat), -a
  • toil f (wish), tola
  • tóin f (arse), tóna, -eanna
  • tost m (silence), -a, -anna
  • troid f (fight), troda, -eanna
  • úr m (heath), -a (as "fresh" in 1st)

Multiple declension nounsEdit

For a list of nouns having third and other declension forms, see the multiple declension table in the Irish nouns appendix.

Wiktionary templatesEdit


  1. ^ When used for verbal nouns, these suffixes are feminine. However, monosyllabic nouns in -áil need to be treated with care. While dáil is third declension but masculine, cáil and sáil are feminine, but second declension.
  2. ^ There are 16 nouns in the list as at 22 Feb 2018, sourced from a trawl of WikiBooks, Nualéargais and An Caighdeán
  3. ^ The lists given here are not intended to be exhaustive. There are 116 nouns in the list as at 08-Mar-2018, sourced from a trawl of the Wiktionary Category, O'Donavan's Irish Grammar, and teanglann

External linksEdit

See alsoEdit