1. Usually proceeded by "the" or "that". It's the imaginary wall that seperates friendship and something confusing, something more. Crossing that line, is usually a bad thing and can be very
costly to a friendship. Once this line is passed, there is no turning back, the door is closed.
2. Any line that separates
good things and
bad things.
1. "I regret that we
crossed that line."
2. "Don't cross the line with that teacher. She'll give you a
referral on the spot."