This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form combines 月 (moon) with 享, but the original semantic and phonetic roles are unclear.
The moon 月 beside 享 suggests a connection to moonlight, but the kanji's meaning is not well defined. Think of it as a rare character possibly related to moonlight.
For トン, imagine a ton of moonlight pouring down from the moon 月: ton -> トン.