una de sus

one of his, her, or their

→ uno
phrase Rare #32,971
one of his, her, or their Used before a feminine singular noun to refer to one item belonging to or associated with a male, female, or plural group. The possessive sus can mean his, her, or their depending on context.
SP: Una de sus películas ganó un premio.
EN: One of his movies won an award.

Una de sus primeras obras.

One of his early works.

— Retrato de una mujer en llamas (2019)

Tom le dio a Mary una de sus guitarras.

Tom gave Mary one of his guitars.

Una de sus colegas está en la casa.

One of her colleagues is at the house.

— El mundo (2004)

Lo llamo para decirle que una de sus máquinas está averiada.

I am calling to tell you that one of your machines is broken.

— Amelie (2001)

Ahí viene una de sus crías.

There comes one of her young.

Una de sus hermanas es enfermera.

One of her sisters is a nurse.

Una de sus aficiones es coleccionar camisetas.

One of his hobbies is collecting t-shirts.

Una de sus fans, seguro es el precio de la fama.

One of his fans—it's probably the price of fame.

— Caché (Escondido) (2005)