From Old Portuguese vosso, from Latin voster, vostrum, from earlier vester, from Proto-Italic *westeros.
vosso m (feminine vossa, plural vossos, feminine plural vossas)
- Second-person plural possessive pronoun.
- your; yours
In European Portuguese it is used with the third person plural (vocês), to avoid the ambiguity of seu which denotes both third person singular and plural:
Não se esqueçam de trazer os vossos fatos de banho.
- Don't forget to bring your bathing suits.
Here the verb esqueçam is conjugated in the third person plural while the possessive pronoun vossos is in the second person plural.
The other common use is in very official forms of address such as Vossa Excelência (president, ministers of state, judges etc.), Vossa Magnificência (dean of a university) or Vossa Senhoria.