ソク, のっと.る, のり
rule, follow, based on, model after
JLPT2 G5 S9 F753
The relevant seal inscription form is an abbreviated form# of 鼎 tripod kettle/cauldron + a knife beside it for cutting food or other objects (compare 析). *Rule* and *law* are abstract, extended meanings (← abide by/*follow* norms closely ← be beside/in line with something) → *at once*; *if so*.
[Full Kanji Etymology List]