This is the 2849th most frequent Japanese word.
おめでとう
"Congratulations."
Used to congratulate someone on their birthday in a formal and polite context.
お誕生日おめでとうございます。
Happy birthday to you.
Used to congratulate someone for achieving a significant milestone or accomplishment, such as passing an exam.
合格おめでとう！
Congratulations on passing the exam!
Used to express happiness and congratulate someone for a significant life event like marriage.