What does the Spanish word ser mean in English?

The Spanish word "ser" is a verb that translates to "to be" in English. It's one of the most fundamental verbs in Spanish, used to express existence, identity, qualities, and states.

Here are some examples:

* Yo soy estudiante. (I am a student.)

* Ella es muy inteligente. (She is very intelligent.)

* El libro es interesante. (The book is interesting.)

* Nosotros somos amigos. (We are friends.)

Keep in mind that "ser" is often used in conjunction with other verbs and prepositions to form more complex expressions.