What’s the difference between “tweeling” and “drieling” in Dutch?

This riddle stumps people on purpose: two boys share the exact same birthday, month, year and parents, yet aren’t tweeling (“twins”). The trick is the word itself — tweeling only ever means exactly two. Swap the number and the pattern holds: drieling is “triplets,” vierling is “quadruplets,” vijfling is “quintuplets.” So the honest answer isn’t “they’re not twins” — it’s that a third sibling exists too.

It’s a well-known Dutch riddle, and the accepted answer is drieling: the two boys are two of a set of triplets, so every fact given (same parents, same birthday) is literally true without them being twins. The same -ling ending shows up in unrelated words too — vreemdeling (“stranger,” someone foreign) and vondeling (“foundling”) — but for births specifically it climbs straight up the numbers: tweeling, drieling, vierling, vijfling, zesling.