当てはまる
あてはまる · atehamaru · JLPT N2 · verb-godan
to be applicable
🧩 当て (apply, put against) + はまる (fit snugly) = it fits the case
当て comes from 当てる, to apply or hold something against. はまる (嵌まる) means to slot neatly into place. Put together: a rule held up against a case that fits it exactly, so the rule applies or the item falls under the category.
当 — small ⺌ + crown 冖 + hand 彐 (simplified from 當: 尚 + 田)
Originally written 當, combining 田 'field' with 尚 as a phonetic. The early sense was 'to match' or 'face' a field of equal value, extended to 'correspond to', 'ought to', and 'serve as'. The simplified form 当 streamlines the upper 尚 component.