A black rectangle with a solid, thick blue line through the middle. Symbol that is put on items ranging from front license plates, pins, bumper stickers (very small sticker),etc that denotes the user is a police officer. It is a violation of many state's laws to display this symbol if the user is not employed by a police agency. Related to this is the Red Line, which is used to identify fire/medical services personnel. These symbols are usually found on the off-duty vehicles or other personal effects of police /emergency services personnel.
My next-door neighbor, who is a highway patrolman, has a Blue Line tag on the front of his car, as well as a Blue Line sticker.
The blue line which appears on the left of the text pane when composing replies in Microsoft Outlook. It is continuous and so cannot be used to distinguish a series of quotes from the original text from the reply text. Nor can it be entirely deleted, as any attempt to do so will leave a one-character sized stub.
Blue Line Special is a southern adjective, noun, and verb. It is insert-able wherever you want it to be, and is usually applied to situations where the speaker is unable to come up with a real word.
mmnmmmhm. we didn't go camping this weekend. thats pretty blue line special.