I am from Spain, but, in Hispano-América, they use "USTEDES" as a synonym of VOSOTROS. However, in Spain we don`t use it in this way :)

Tú - 2nd person singular. It's the equivalent of "you" in English when used among friends, family, and people younger than you (as a rough guideline) Usted (Ud)- 2nd person singular for formal use-the equivalent of "you" when you are talking to someone older than you, someone in a position of respect, or a stranger Ustedes (Uds.) 2nd person plural--the same use as Ud but when you are talking to two or more people, if you'd use Ud with at least one of them. Uds is also used widely in Latin America for all cases of the 2nd person plural instead of vosotros/as, which is commonly used in Spain as the plural of "tú". So the different between tú and usted boils down to how well you know someone or what your status is relative to theirs (a kid would use Ud with most adults, most adults will use tú with a kid). The difference between using both vosotros/as and ustedes or just ustedes depends on where you are speaking Spanish :) Nosotros is the first person plural ("we") if even one person in that "we" is a man. For groups of only women, it is "nosotras". Somos is just the 1st person plural present conjugation of "ser" eg Nosotros somos. Nosotras somos.

Gracias

ustedes es plural

Nosotros is used for masculine gender and nosotras for feminine gender. Usted is formal way and Tu is informal way of you.