唇

1. Origins, structure, and basic meaning

• Structure: 唇 is read as くちびる and is a noun for the lips forming the outer edge of the mouth.
• Basic usage: Lips becoming dry appears in 唇が乾く, while putting a finger to the lips appears in 唇に指を当てる.

2. Common pitfalls and similar expressions

• Particles for a state and contact
  • The lips take が as the subject of a state and に as the place touched by a finger.
• Difference from 口
  • Unlike the broad word for the mouth or oral opening, this term specifically denotes the outer lips.