勤める
つとめる · tsutomeru · JLPT N5 · verb-ichidan
to work (for)
🏢💼 tsutomeru: 勤 = diligence, the same kanji as in 通勤 (commute) and 勤務 (duty)
勤 carries the sense of diligent service, and 勤める means being employed by an organisation. The employer takes に: 銀行に勤める = to work for a bank. Compare 働く, which is working in general, not for someone.