This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
墇 combines 土 (earth) with 章, which likely provides the sound. The exact historical development is uncertain.
The earth radical 土 beside 章 suggests something related to soil or a barrier, but the meaning is not well established.
For ショウ, imagine a show (ショウ) being performed on an earthen stage made of 土, with 章 as the backdrop.