This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development is uncertain. The modern form combines 規 on top and 鬲 on the bottom, but the original semantic and phonetic roles are unclear.
No clear meaning is available, so a mnemonic based on shape alone is unreliable. The top 規 suggests a compass or rule, and the bottom 鬲 is an ancient cooking vessel, but the combined idea is obscure.
For キ, imagine a key unlocking an ancient vessel: key -> キ, and the vessel 鬲 sits beneath the rule 規.