Dictionary.com
definitions

Loschmidt's number

[loh-shmits]
noun Chemistry.
  1. the number of molecules in one cubic centimeter of an ideal gas at standard temperature and pressure, equal to 2.687 × 1019.
Compare Avogadro's number.

Origin of Loschmidt's number

after Joseph Loschmidt (1821–95), Austrian chemist, who calculated it
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018