相对
xiāngduì · HSK 7
be opposite
相 mutual + 对 facing = mutually facing, opposite each other
相 carries the sense of one-another or mutual, and 对 means to face or be correct/opposite. Together 相对 is two things set facing one another, hence opposite or relative to each other.
对 — 又 (hand) + 寸 (measure/rule)
Originally depicted a hand (又) holding or responding to something, with 寸 added as a phonetic-semantic element suggesting measured action. The traditional form 對 showed a hand presenting an object in reply, giving the core sense of 'to answer' or 'face toward.' Modern meanings like 'correct' and 'pair' grew from this idea of matching response.