In association football, a cross is a medium- to-long-range pass from a wide area of the field towards the centre of the field near the opponent's goal. Specifically, the intention of a cross is to directly bring the ball into the box from an angle that allows the attacking forwards to more easily aim for goal with their head or feet. Crosses are generally airborne (floated) to clear nearby defenders, but can also be hit with force along the ground (drilled). It is a quick and effective move.
Crosses are primarily used to create goal-scoring efforts, and form an important repertoire of counter-attacking tactics and wing-play. Players in wide positions, usually wingers, wingbacks and fullbacks, deliver the ball into the penalty box, close to the opponent's goal. Team-mates in the central positions, typically forwards, attempt to volley or deflect the delivered ball with their head or feet, depending on the height of the delivery, towards the goal and hopefully scoring.
As an attacking move, the cross is typically seen when the player is running towards their opponents, so it is easier to use the insole of the "outside" foot (i.e. the right foot if on the right side of the field and vice versa) to deliver the cross. For this reason, it is more common to see crosses from players playing on the same side of the field as their dominant foot (conventional wingers), although it is not uncommon to see talented wingers on opposite wings (inverted wingers) carry out feints and manoeuvres to get into a position where they can cross with the other foot (see Cruijff turn).
Depending on the intention and skill of the crosser, a cross can be a speculative way to create a half-chance by playing the ball into a dangerous area, or an accurate way to find a team-mate in a more central position, or something in between. In terms of tactics, the crosser can choose whether to initiate a cross from a deeper position(sacrificing angle for a quicker attack), or from a forward position (when the team-mate is more likely to be facing the goal, but may have more defenders around them). Similarly, the crosser can vary the height, speed and curl on the ball to evade defences. Attributes like pace, kicking technique and positional awareness are valuable when looking for good crossers. Similarly, good positioning, heading and volleying attributes and a physical presence allows the target of the cross to stave off defenders and react well to the cross.