Definitions
1.nounA time limit in the form of a date on or before which something must be completed."I must make this deadline or my boss will kill me!"
2.nounA guideline marked on a plate for a printing press.
3.nounA line that does not move.
4.nounA boundary around a prison, prisoners crossing which would be shot.
5.verbTo render an item non-mission-capable; to ground an aircraft, etc.