1Happiness, blessedness, or good fortune (a state of being fortunate); also commonly used as a polite closing phrase in requests, as in '〜ていただければ幸いです' (I would be grateful if...).
あなたの無事が何よりの幸いです。
Your safety is the greatest happiness of all.
ご都合がよろしければ、来週の説明会にご参加いただければ幸いです。
If it's convenient for you, I would be grateful if you could attend next week's briefing session.
家族が元気でいることが彼の幸いだ。
His happiness is that his family is healthy.
小さな親切が大きな幸いをもたらした。
A small kindness brought great good fortune.
2Luckily; fortunately — used adverbially to indicate something happened to good effect.
幸い、会議は予定より早く終わった。
Fortunately, the meeting ended earlier than scheduled.
幸いにも彼が近くにいて助かった。
Fortunately, he was nearby and helped.
交通事故にならず、幸いでした。
It was fortunate that there was no traffic accident.