皮膜

1. Origins, structure, and basic meaning

• Structure: 皮膜, read ひまく, means a thin layer covering a surface.
• Basic usage: It is used when observing a thin layer formed on a metal or liquid surface.
  • 金属の表面に薄い皮膜が形成されていた。

2. Common pitfalls and similar expressions

• What is covered: distinction from 皮膚
  • 皮膚 refers to human or animal skin, while 皮膜 can also refer to a film on metal or liquid. The presence of 皮 does not restrict the word to biological skin.