Old Irish ā-stem nouns.

These nouns are feminine, typically with the following endings:

• in the nominative singular: the bare stem with lenition of the following word;
• in the genitive singular: -e with palatalization of the last stem consonant and aspiration/gemination of the following word;
• in the nominative plural: -a with aspiration/gemination of the following word.

The stem classes are named from the perspective of Proto-Celtic and may not still be visible in Old Irish inflections. Sometimes the nominative singular ended in a palatalized consonant by analogy with the dative singular.