red line: Meaning and Definition of

red' line"

1. a line of the color red that is parallel to and equidistant from the goal lines and divides the rink in half.

red•line

1. to treat by redlining (an area or neighborhood).
2. to establish the recommended safe speed of (an airplane): The bomber is redlined at 650 miles an hour.
3. to draw a canceling red line through (an item on a list).
4. to mark or designate for cancellation, rejection, dismissal, or the like: club members redlined for unpaid dues.
5. to cause (an airplane) to be grounded.

1. to engage in redlining.

1. the maximum rotational speed, or angular velocity, of the engine crankshaft that is considered safe: often measured in rpm.
2. a red line or boundary of a red area that delineates such a value, as on a tachometer.