一切經音義 8.32

8.32

儵忽（識祝反王逸注楚辭儵忽急皃也又云儵忽如電光也廣雅儵忽光從黑攸聲也攸音由或從火作倐或從足作跾皆古字也）。

Fleeting and sudden (儵忽: shi-zhu [fanqie]. Wang Yi's commentary to the Chuci says: "儵忽 means a swift appearance." He also says: "儵忽 like a flash of lightning." The Guangya says: "儵忽 means light; it takes its semantic classifier from 黑 'black' and 攸 is the phonetic." 攸 is read you. It is also written with 火 as 倐, or with 足 as 跾, all being ancient characters).