This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
琩 is a rare character composed of 王 (jade) and 昌 (prosperous). It likely relates to a type of jade ornament, but its exact historical development is uncertain.
The left side 王 suggests jade, and the right side 昌 suggests brightness or prosperity. Picture a bright, prosperous jade ornament, though its exact meaning is unclear.
For ショウ, imagine showing (ショウ) a bright jade ornament: show -> ショウ, and the jade shines.