nuestro
/ˈnwestɾo/ · A1 · pron
our, ours, to us
nuestro = nos (us) + -tro; from Latin noster, as in Pater Noster = Our Father
The nos- root means we/us (nosotros, nos). Latin noster became nuestro as stressed o turned into ue, the same shift as porta to puerta. It pairs with vuestro (yours), from vos, and changes ending: nuestra, nuestros, nuestras.