This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form visually contains 廛 and ⻏, but the original component relationships are unclear.
The kanji has no clear meaning, so a mnemonic is not possible. Focus on recognizing its shape.
For テン, imagine a rare shop sign with the number ten on it: ten -> テン, but the shop's name is unknown.