とん

adverb taking the 'to' particle, adverb

tap; knock; bonk

Mimetic word for a light, short tapping or knocking sound, often used with と or as an adverb.

• 誰だれかがドアをとんとんとノックした。

  Someone tapped lightly on the door.

• 肩かたをとんと叩たたかれた。

  I was tapped on the shoulder.