noun
A unit of length equal to one millionth of a meter. Now officially called マイクロメートル in Japanese, but ミクロン remains common in everyday and industrial contexts.
from French
このフィルターは0.5ミクロンの粒子を除去できます。
This filter can remove particles of 0.5 microns.
髪の毛
The thickness of a human hair is about 70 microns.