off-side rule

English

Etymology

The computer-programming sense was coined by British computer scientist Peter Landin in 1966 and named after the rule in football.

Noun

off-side rule

1. (soccer) The prohibition of teammates closer to the opponents' goal than the person kicking or throwing the ball unless there are three opponents at least as close to their goal line.
   • 1889, Badminton Library of Sports and Pastimes - Volume 20, page 277:

     For the time the Etonians had their way, and it was not until 1867 that the Association adopted its present off-side rule, which provides that no man can be ' off-side ' unless there are less than three players of the opposite side in front of him when the ball is passed.

   • 1897, Hoffmann, Every Boy's Book of Sport and Pastime, page 429:

     To the unintelligent or careless, the great stumbling-block is Law 6, known as the off-side rule. It is of itself a reflection on the bulk of young players that this particular provision is so little understood, or rather so misunderstood. The rule provides that when a player kicks the ball, or throws it in from touch, any one of the same side who at such moment of playing or throwing is nearer to the opponents' goal-line, is out of play, and may neither touch the ball himself, nor in any way whatever prevent other players from doing so, until the ball as been played, unless there are at such moment of kicking or throwing, at least three of his opponents nearer their own goal-line.

   • 2010, Will Rollason, We Are Playing Football, →ISBN:

     The off-side rule in football states that no player may be closer to his opponents' goal than his last two opponents (usually a defender and the goalkeeper) and the ball at the time the ball is kicked forwards towards him.

2. (traffic engineering) A system that gives right-of-way at an intersection to traffic approaching from the side on which one is not driving.
   • 1955, The Motor - Volume 107, page 555:

     An off-side rule would work splendidly at even the most complex junctions.

   • 1969, Australian Road Research - Volume 4, page 15:

     According to the off-side rule, a priority vehicle relative to the driver's own vehicle is one which approaches on the nearest carriageway of the crossing road.

   • 2017, Reg Shaw, Teach Yourself Cycling: The classic guide to life on two wheels, →ISBN:

     In France and Switzerland at the present time it is traffic coming from the right (that is to say, the near side) which has priority, but there are many advocates of a change to an “off-side rule”.

3. (programming) In some programming languages, the convention by which the indentation of a line of source code affects its meaning.
   • 2018, Encyclopedia of Bioinformatics and Computational Biology, Elsevier, →ISBN, page 195:

     Blocks in Pythons are delimited by white space indentation: the increase in indentation delimited the start of statements while the decrease signifies the end of the current block (off-side rule).