The line seen on a person's jaw or neck when their face makeup is too dark (or light) for their real skin tone.

Phrase used on some message boards to refer to the famous line from Snakes on a Plane, that line being "I've had it with these motherfucking snakes on this motherfucking plane!"

To set someone up(Toronto)

Although one of the least common definitions, a "line" can also mean 1 fluid oz of codeine cough syrup. For example, some people who sell the stuff will sell it by the "line" for anywhere from like 30-100 dollars.

Set someone up, plot against, conspire against one.

in a position of risk or vulnerability.

An imaginary line, that which loud managers insist you bring product forward to on the shelf.