About this word

Cathair is a feminine noun, meaning both city and stone fort. (As with many homographs, including English ones, the intended meaning only becomes clear when given context: Polish furniture with polish… German furniture with none.)

As here, when prepositions are followed by the singular definite article, an, they usually cause eclipsis (if the following noun starts with an ecliptable consonant): as an gcathair (from the city), ar an gcathair (on the stone fort), ar an nguthán (on the phone), faoin mbord (under the table) ⁊rl…

Exceptions are the prepositions i, de and do:

• i + an becomes sa before consonants. This is usually (but not always) followed by lenition in Munster and Ulster Irish, and by eclipsis in Connacht Irish.
• de + an becomes den before consonants. This may be lenited or eclipsed.
• de + an becomes don before consonants. This may be lenited or eclipsed.