This is the 8179th most frequent Portuguese word.
susana
"Susana" is a Portuguese feminine given name, equivalent to "Susanna" or "Susan" in English.
In this sentence, 'Susana' is a proper noun referring to a person's name acting as the subject of the sentence.
Susana comprou um vestido bonito para o casamento.
Susana bought a beautiful dress for the wedding.
Here, 'Susana' is again a proper noun indicating the person who is the focus of the discussion.
Eu acho que Susana gosta de viagens internacionais.
I think Susana likes international travel.
In this case, 'Susana' is a proper noun used as the subject performing the action.