Invisible Boundary That Is Not to Be Crossed
This page is the CodyCross answer for the clue below from Space Exploration, Group 913, Puzzle 5 (Andromeda Galaxy).
Question is: Invisible Boundary That Is Not to Be Crossed
and the answer is: REDLINE
Word Meaning:
RED LINE — (ice hockey) The thick red line on the ice which divides the rink in half.
Definitions from Wiktionary.