Learn Romanian: Femeia este o mătușă a ei. - The woman is an aunt of hers.

In Romanian, when a noun is indefinite (like o mătușă, meaning an aunt) and is followed by a possessor, you must use a linking article. You cannot just put the possessor right next to the noun like you do with definite words. Since mătușă is feminine and singular, the linking article is a.

Wait, earlier we learned mătușa ei for her aunt. Why is it o mătușă a ei here?

That is exactly what this lesson teaches! mătușa ei means her aunt (using a definite noun). But this sentence says she is an aunt of hers, which uses the indefinite article o. Because the noun is indefinite, Romanian grammar requires the linking article a to connect o mătușă to the possessor ei.

If the sentence was about an uncle instead of an aunt, would the word a change?

Yes! The linking article always matches the gender and number of the noun being possessed. Since mătușă is feminine singular, we use a. If the word was un unchi (an uncle), which is masculine singular, you would use al to say un unchi al ei (an uncle of hers).

What exactly does ei mean in this sentence?