Final answer:
The Spanish word for "they" is "ellos".
Step-by-step explanation:
The Spanish word for "they" when referring to both a boy and a girl is ellos. In Spanish, the pronoun "ellos" is used to refer to a group of people that includes both males and females. For example, if you want to say "They are going to the store", you would say "Ellos van a la tienda".
Learn more about Spanish pronouns