This is the 25th most frequent Japanese word.
なる
"なる" means "to become."
Here, 'なる' is used to indicate a transformation or change of state, meaning 'to become'.
新しい部署の一員になる予定です。
I plan to become a member of a new department.
Here, 'なる' expresses the goal of achieving a specific profession or state, meaning 'to become' as a personal aspiration.
彼は医者になりたがっています。
He wants to become a doctor.
In this context, 'なる' signals the arrival or occurrence of a time or condition, meaning 'to come to be' or 'to occur'.