red line

1. 1.

   a line that is colored red and that bisects an ice hockey rink

   Broaderline

Questions about red line

What does red line mean?

red line means "a line that is colored red and that bisects an ice hockey rink".

Is red line a common word?

red line is banded "Uncommon" — turns up in careful writing rather than conversation. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.