湯気

1. Origins, structure, and basic meaning

• Structure: 湯気 (ゆげ) is a noun for steam rising from hot water or food.
• Basic usage: In 湯気が上がる the steam is what rises; in 湯気で曇る it is the cause of the fogged glass.

2. Common pitfalls and similar expressions

• Visible steam and its fogging effect
  • 湯気 is the visible steam rising from hot liquid or food. When it reaches glass or a lens, it can fog the surface.