Spanish Grammar/Possessive pronouns
1st person mi (my) nuestro/nuestra (our (m)/(f))
2nd person tu (your) vuestro/vuestra (your (plural informal) (m)/(f))
3rd person su (his/her/your (formal)) su (their (m)/(f)/your (plural formal))
Note: Both singular and plural possessive pronouns can modify either singular or plural nouns and are declined to agree in gender and number with the noun they modify.
ex. mi maleta/mis maletas – my suitcase/my suitcases
nuestra maleta/nuestras maletas – our suitcase/our suitcases