一切經音義 86.87

86.87

噓氣（上許居反考聲噓開口出氣說文云噓吹噓也從口虛聲）。

Breathing out (噓氣: the first [character] is *xu-ju* [x- + -ū = xū] in fanqie; the Kaosheng says: “噓 means opening the mouth to exhale breath.” The Shuowen says: “噓 means to blow or exhale; it is categorized under 'mouth' with 虛 as phonetic”).