This is the 5128th most frequent Japanese word.
転機
Turning point; critical juncture.
The word "転機" is used here to signify a significant change or turning point in the speaker's life due to starting a new job.
新しい仕事を始めた時、人生にとって大きな転機となりました。
When I started a new job, it marked a major turning point in my life.
In this sentence, "転機" conveys an important change or event influencing not just an individual but an entire group (the family).
彼が留学するという決断は、家族全体にとっての転機だった。
His decision to study abroad was a turning point for the entire family.
Here, "転機" is used to refer to a potential defining moment that could lead to future success or change.