fixed law; established rule
A formal term for a law or rule that is fixed and unchanging, often used in legal, philosophical, or scientific contexts.
According to the fixed laws of nature, planets revolve around the sun.
There are implicit fixed rules in this society.
Composed of 定 (fixed, determined) and 律 (law, rule). The exact historical derivation is uncertain, but the kanji combination directly conveys the meaning of an unchanging law.