制約
せいやく · seiyaku · JLPT N1 · noun
restriction
⛓️ 制 (control) + 約 (bind) = limits that bind you
制 means control or restrict, and 約 means bind or promise. Together they name a limit that binds you, like a rule you must keep.
制 — knife 刂 + 未 (tree branches)
Originally depicted a knife 刂 cutting branches from a tree, showing the act of trimming or shaping wood. From this concrete sense of cutting to size came the meanings 'to make,' 'to manufacture,' and by extension 'to control' or 'regulate' — shaping things to a desired form.