續一切經音義 3.193

3.193

瞬息（上式𨳝反說文云目動睫也考聲云目搖動也謂眸子轉也又作瞚眴義同下相即反藥證病源云凡人晝夜共一萬三千三百息一息有差即為病矣梵云阿那鉢那此云出息入息也）。

Instant of breath (瞬息: for the upper, shì + yù [shùn]; the Shuowen says, "Movement of the eye and lashes." The Kaosheng says, "The shaking and moving of the eyes; it refers to the rolling of the pupils." Also written as 瞚 and 眴 with identical meaning. For the lower, xiāng + jí [xī]; the Yaocheng bingyuan says, "In an ordinary human being over a day and night there are altogether 13,300 breaths; if even one breath goes awry, it becomes an illness." In Sanskrit it is ānāpāna, rendered here as exhalation and inhalation).