from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A part or other object per thousand.
Sorry, no etymologies found.
It should have small effect in distance 5 billion years ago vs. today. relatively not a big thing, less than permille of mass per 10 billion years
Typically uncooled particle beams have dimensions in the mm-cm range and momentum spreads in the permille-percent range.
» while composing the percent sign with the letter O results in the permille sign ‰.