This is the 7548th most frequent Portuguese word.
ovnis
"OVNIs" in Portuguese means "UFOs" (Unidentified Flying Objects).
Here, 'ovnis' is used as the subject of the sentence to refer to unidentified flying objects.
Os ovnis são frequentemente associados a fenômenos inexplicáveis.
UFOs are often associated with unexplained phenomena.
'Ovnis' is the direct object of the verb 'ter visto', indicating actually sighting unidentified flying objects.
Algumas pessoas afirmam ter visto ovnis sobrevoando a cidade.
Some people claim to have seen UFOs flying over the city.
'Ovnis' here is part of a prepositional phrase ('com ovnis'), referring to the objects encountered as part of such stories.