鈉
Sodium (element), natrium, sharpen wood
Readings
On'yomi
- ドウ
- ノウ
Kun'yomi
- きた.える
Meaning
鈉 has two distinct meaning clusters: one is the chemical element sodium (natrium), and the other is the action of sharpening wood. These senses do not share a single clear conceptual center.
Study
Etymology
鈉 is a phono-semantic compound: 金 (metal) suggests a metallic element, and 内 likely contributes the sound. The 'sharpen wood' sense may be a separate usage or a later extension, but the exact historical development is uncertain.
Meaning mnemonic
Metal (金) inside (内) a wooden tool: imagine a metal blade embedded inside a wooden handle, used to sharpen wood. For sodium, picture a shiny metal (金) stored inside (内) oil to prevent it from reacting.
Reading mnemonic
For ドウ, imagine a sodium metal bar being sharpened into a wooden dowel: dowel -> ドウ, and the metal inside the wood makes it strong.