瞳孔

1. Origins, structure, and basic meaning

• Structure: 瞳孔 is read as どうこう and is a noun for the pupil, the central opening through which light enters the eye.
• Basic usage: Use 瞳孔の変化 for a change in state and 瞳孔が細く見える for how its shape appears.

2. Common pitfalls and similar expressions

• Whole eye and pupil
  • 瞳孔 names one part inside the eye, whose appearance can vary with brightness, rather than the entire eye.
• Observation and depiction
  • One context examines change with a model; the other depicts a cat's pupils as looking narrow in a drawing.