This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 墏 is uncertain. It visually combines 將 on top and 土 (earth) below, but the original semantic and phonetic roles are unclear.
With 將 (general) over 土 (earth), imagine a general standing on the earth, but the meaning remains unclear.
For ショウ, picture a general (将, ショウ) standing on the earth: 将 -> ショウ, and the earth supports the general.