This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 廫 is uncertain. It visually combines 广 (building enclosure) with 膠, but the original component relationship is unclear.
The outer 广 suggests a building, and the inner 膠 (glue) might hint at something stuck or empty inside, but the meaning is too uncertain for a reliable mnemonic.
For リョウ, imagine a rare, empty room (リョウ) inside the 广 building, echoing the uncertain, hollow feeling of the kanji.