適用
てきよう · tekiyou · JLPT N3 · noun
applying
📜 適用 = suitable + use → put a rule to use where it fits
適 (てき) means suitable or fitting, as in 適当; 用 (よう) means use, as in 利用. Using something where it fits is applying it, e.g. 法律を適用する, to apply the law.
用 — pictograph of a bucket or wooden pail
用 originally depicted a bucket or container, possibly a sacrificial vessel made of wood. Over time it was borrowed to mean 'to use' or 'employ,' losing its concrete object sense. The modern meaning 'use' has been standard since early classical Chinese.