also: いったんじ
noun
brief moment; instant; twinkling of an eye
Literary or Buddhist term for an extremely short time, comparable to a finger snap. Rare in modern everyday speech.
一弾指の間にすべてが変わった。
Everything changed in the twinkling of an eye.
Buddhist term originally referring to the time it takes to snap one's fingers. The exact historical derivation is uncertain, but it is a classical Chinese compound adopted into Japanese.