薬指
くすりゆび · kusuriyubi · JLPT N2 · noun
ring finger
💍 Compound: 薬 (medicine) + 指 (finger), the finger traditionally used to stir medicine
Traditionally said to be named for stirring powdered medicine with this finger, since it was seen as the weakest and least-used finger. Wedding rings are usually worn on it.
指 — hand radical 扌 + 旨 (zhǐ, phonetic)
指 is a semantic-phonetic compound. The hand radical 扌 gives the meaning — something done with the hand, namely pointing with a finger. 旨 supplies the sound 'zhǐ'. From 'finger' it naturally extended to the verb 'to point' and figurative senses like 'to indicate' or 'to refer to'.