Quietness, Calmness; Lack of Movement
This page is the CodyCross answer for the clue below from Physics, Group 1887, Puzzle 5 (Particle Accelerator).
Question is: Quietness, Calmness; Lack of Movement
and the answer is: STILLNESS
Word Meaning:
STILLNESS — The quality or state of being still.
Definitions from Wiktionary.