Learn Dutch: De nicht van mijn oom heet Eva. - My uncle's niece is called Eva.

You actually can say mijn ooms nicht, but using van (meaning "of") is the most common and natural way to show possession in everyday Dutch. The possessive -s is mostly reserved for proper names (like Eva's) and a few close family terms when used on their own without "my" or "the" (like vaders or moeders).

Does nicht mean "niece" or "cousin" here?

It could be either! In Dutch, nicht is used for both a "niece" and a "female cousin." You usually have to rely on the context of the conversation to know which one is meant. (The male equivalent, neef, works exactly the same way for nephews and male cousins).

The English translation says "is called," but there is only one verb (heet) in Dutch. Why?

While English uses a combination of words like "is called" or "is named," Dutch has a specific, single verb for this action: heten. Because the subject here is singular (de nicht), we use the form heet.

Why does the verb heet come all the way after oom?

In a standard Dutch sentence, the main verb must sit in the second position. The entire phrase De nicht van mijn oom (The niece of my uncle) counts as just one "block" of information—the subject. Therefore, the verb heet takes the second spot right after that entire block.