I.up [美 əp, 英 ʌp]副up often appears as the second element of certain verb structures in English (back up, pick up, sit up, etc). For translations, see the relevant verb entry (back, pick, sit, etc).
An audible theme is picked out, and during a "piano" and staccato repetition of the theme, the strings and flutes rush up, bringing the music to the briefest of halts.