Circumference or Outer Edge
This page is the CodyCross answer for the clue below from Physics, Group 1882, Puzzle 3 (Interstellar Medium).
Question is: Circumference or Outer Edge
and the answer is: PERIMETER
Word Meaning:
PERIMETER — (mathematics) The sum of the distance of all the lengths of the sides of an object.
Definitions from Wiktionary.