English words from Old Irish
- DeclanA male given name from Old Irish, borne notably by Declán of Ardmore
- rathA walled enclosure, especially in Ireland; a ringfort built sometime between the Iron Age and the Viking Age.
- emerA female given name from Old Irish.
- ConnachtThe western province of Ireland, inclusive of the counties Galway, Leitrim, Mayo, Roscommon, and Sligo.
- rannA stanza of Irish poetry.
- AdamnanAn Irish saint (c. 624–704), patron saint of the Diocese of Raphoe, the biographer of St. Columba and an acquaintance of the Venerable Bede.
- AífeA female warrior from Alba (Scotland), the daughter of Airdgeimm and sister of Scáthach, who became Cú Chulainn's lover; featured in the Ulster Cycle.
- AirgiallaA medieval overkingdom encompassing present-day Ireland.
- Cú ChulainnThe pre-eminent hero of Ulster in the Ulster Cycle, almost undefeatable due to his spear the Gae Bulg, but cursed to reach an early grave; son of Lugh and Deichtine.
- erenaghThe head of a clan occupying church lands under a bishop in Gaelic Ireland.
- immramAn Old Irish tale of a sea voyage to a mythical land.
- tuathA tribe or group of people in Ireland, having a loose voluntary system of governance entered into through contracts by all members.