íarn

Old Irish

íarn n or m (genitive íairn or éirn, nominative plural íairn or éirn)

Disyllabic declension if neuter:

Neuter o-stem
	Singular	Dual	Plural
Nominative	íarn^N	íarn^N	íarn^L, íarna
Vocative	íarn^N	íarn^N	íarn^L, íarna
Accusative	íarn^N	íarn^N	íarn^L, íarna
Genitive	ïairn^L	íarn	íarn^N
Dative	ïurn^L	íarnaib	íarnaib
Initial mutations of a following adjective: ^H = triggers aspiration ^L = triggers lenition ^N = triggers nasalization

Monosyllabic declension if neuter:

Neuter o-stem
	Singular	Dual	Plural
Nominative	íarn^N	íarn^N	íarn^L, íarna
Vocative	íarn^N	íarn^N	íarn^L, íarna
Accusative	íarn^N	íarn^N	íarn^L, íarna
Genitive	éirn^L	íarn	íarn^N
Dative	íarn^L	íarnaib	íarnaib
Initial mutations of a following adjective: ^H = triggers aspiration ^L = triggers lenition ^N = triggers nasalization

Disyllabic declension if masculine:

Masculine o-stem
	Singular	Dual	Plural
Nominative	íarn	íarn^L	ïairn^L
Vocative	ïairn	íarn^L	íarnu^H
Accusative	íarn^N	íarn^L	íarnu^H
Genitive	ïairn^L	íarn	íarn^N
Dative	ïurn^L	íarnaib	íarnaib
Initial mutations of a following adjective: ^H = triggers aspiration ^L = triggers lenition ^N = triggers nasalization

Monosyllabic declension if masculine:

Masculine o-stem
	Singular	Dual	Plural
Nominative	íarn	íarn^L	éirn^L
Vocative	éirn	íarn^L	íarnu^H
Accusative	íarn^N	íarn^L	íarnu^H
Genitive	éirn^L	íarn	íarn^N
Dative	íarn^L	íarnaib	íarnaib
Initial mutations of a following adjective: ^H = triggers aspiration ^L = triggers lenition ^N = triggers nasalization

Old Irish mutation
Radical	Lenition	Nasalization
íarn (pronounced with /h/ in h-prothesis environments)	unchanged	n-íarn
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.

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