腕

1. Origins, structure, and basic meaning

• Structure: 腕 is read as うで and is a noun with two senses: a physical arm and skill developed through practice.
• Basic usage: It is used for reaching out an arm and for improving one’s woodworking ability.

2. Common pitfalls and similar expressions

• Physical sense
  • In 腕を伸ばす, it is the actual arm, corresponding to English arm.
• Skill sense
  • 木工の腕を上げる is an idiomatic pattern for improving woodworking skill, not raising a body part.