This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 朒 is uncertain. It visually combines 月 (moon or flesh) with 肉 (meat), but the original semantic and phonetic roles are unclear.
The left side is 月 (moon or flesh) and the right side is 肉 (meat). Picture a piece of meat under the moonlight, but the meaning remains unclear.
For ニク, the right side 肉 itself is read ニク, so remember the reading by seeing the meat component: 肉 -> ニク.
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