This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 抍 is uncertain. It visually combines 扌 (hand) with 升, but the original semantic and phonetic roles are unclear.
The hand radical 扌 beside 升 suggests an action involving a measuring box or scoop, but the exact meaning is unclear.
For ショウ, imagine a hand holding a small measuring box: the box is a 'show' of capacity, and 'show' cues ショウ.