This is the 313th most frequent Greek word.
αυτοί
"They."
Here, 'αυτοί' serves as the subject pronoun for a group of people, indicating plurality and specifically masculine gender or a mixed-gender group.
Αυτοί βλέπουν την παράσταση.
They are watching the performance.
In this case, 'αυτοί' is used as the subject pronoun in a state-of-being sentence, emphasizing the individuals being referred to.
Αυτοί είναι οι δάσκαλοι μας.
They are our teachers.
Here, 'αυτούς' is derived from 'αυτοί' as its accusative form, referring to the direct object of the verb in the sentence.