顎

1. Origins, structure, and basic meaning

• Structure: 顎, read あご, refers to the jaw or chin.
• Basic usage: It can refer to the jaw involved in chewing or the lower part of the face where someone rests a hand.
  • 硬い物をかんだら顎が痛くなった。

2. Common pitfalls and similar expressions

• English jaw versus chin
  • jaw fits a focus on chewing or the jawbone, while chin fits the projecting lower part of the face.