押す
おす · osu · JLPT N5 · verb-godan
to push
👉🔘 押 = hand 扌 + shell 甲: a hand pressing down on a hard shell
The left side 扌 is the hand radical, found in many hand-action verbs. The right side 甲 means shell or armour. A hand bearing down on something hard gives push, press, and stamp. Sound hook: osu, like the karate greeting osu, said with a firm push of breath.
押 — hand radical 扌 + 甲 (jiǎ, phonetic)
押 is a semantic-phonetic compound. The hand radical 扌 supplies the meaning of pressing or holding down with the hand, while 甲 gives the sound. From the literal sense of pressing, it extended to signing/sealing documents, mortgaging, and detaining — all involving an authoritative 'pressing' action.