also: あ
Expresses sudden realization, recollection, or mild surprise. Often used when something comes to mind.
あっ、財布を忘れた。
Ah! I forgot my wallet.
Oh, now that you mention it, tomorrow is a holiday.
Used to get someone's attention, often with a slight sense of urgency or calling out.
あっ、ちょっと待って！
Hey, wait a moment!
Mixed-kana variant, occasionally seen in informal writing.