utvrda

1. Croat. fortress; stronghold; fort
   Na brdu iznad sela su ostaci stare utvrde. — On the hill above the village are the remains of an old fortress.
2. Croat. (figurative) bastion; stronghold
   Ovaj grad je poslednja utvrda opozicije. — This town is the opposition's last stronghold.

The word is typical of Croatian. In Serbia: tvrđava or utvrđenje, and in the figurative sense uporište; utvrda appears mainly in historical and tourist texts.