1. bang; bam; boom; thud; thump; crash
その時、ドンと背中に軽い衝撃を受けた。At that moment, I felt a light thud on my back.
2. noontime signal gun (carried out early Meiji to Taishō); noon gun; noonday gun
3. last round in a game of 12 rounds
4. precisely; exactly; plumb; totally; very