Thanks to Andy Pilkington for the Glossary

Accidentally offside -A player is accidentally offside if (s)he cannot avoid contact with an opponent while being in an offside position. A scrummage is formed at the place where his/her team last played the ball. 

Advantage -A method of refereeing. The referee allows the game to proceed uninterrupted as long as the ball is in play and there are no major infringements. Play can continue after an infringement if the non-offending team gains an advantage.

Back Row -The two flankers and the No. 8, lined up for a scrum.

Backs -The group of players normally numbered 9 through 15 who do not participate in scrums and lineouts, except for the scrumhalf.

Back three -The two wingers and the fullback.

Binding -The careful method players grip and grasp each other to form a secure scrum, ruck, or maul. This is a critical skill to ensure the safety of players.

Blindside -From a set piece, ruck or maul, the short side of the field. Also called the weakside.

Breakdown -Area where there has been a tackle or the ball is loose on the ground.

Charge down -Blocking a kick by the opponent.

Chip Kick -A short shallow kick usually delivered over the head of an onrushing defender to be quickly retrieved or caught by the kicker or one of his/her supporting players.

Clearance Kick -A kick of the ball to touch which relieves pressure on a side under heavy attack by the opposition.

Contact -Where two players come together. Usually in a tackle situation.

Conversion Kick -A kick at the posts after the awarding of a try scoring two points if successful. The kick must be attempted directly from a spot perpendicular to the spot where the try was awarded. Usually taken with a place kick, it can be rushed when the kicker makes a move towards the ball. If taken as a drop kick it is uncontested.

Dead ball -The ball becomes dead if it goes out of bounds or if the referee stops play for any reason.

Dead-ball line -One of two lines marking the lengthwise boundaries of the field, located at the back of the in-goal area, a maximum of 22 metres from the try-line.

Drop goal -A drop kick at the posts, worth three points if successful.  Drop goals can be attempted at any time during open play.

Drop kick -A kick on which the ball is dropped to the ground and kicked just as it bounces.

Dummy -A technique where one pretends to pass the ball (i.e. a fake).

Feed -The rolling of the ball into the scrum by the scrumhalf. Must be straight down the tunnel.

Fifteens -The name of the most common game of rugby union featuring fifteen total players per side. Each team consists of 8 forwards and 7 backs playing two halves each 40 minutes long.

Flag –A non-contact version of rugby in which tackles are simulated by the removal of flags from a belt worn around each player’s waist.  Also called tag rugby or mini tag.

Flanker -Either of the two forwards wearing No. 6 or No. 7. Also called wing forwards or breakaways they bind to the scrum outside of the locks just behind the outside hip of the props. They can play always on the same side of the scrum or can specialize on either the weakside or strongside. The players with the fewest set responsibilities, their job is to aggressively pursue the ball, gain possession, and take off running. Also known as Breakaway Forward.

Flyhalf -The back wearing No. 10 who normally receives the ball from the scrumhalf. Also called the Outhalf, Outside half or 1st 5/8th, he/she will call plays for the backline, pass the ball to other backs, or provide most of the tactical kicks.

Foot Up -An offense where a hooker brings his foot into the scrum's tunnel before the ball is fed by the scrumhalf.

Forward -One of a group of eight players, usually Nos. 1 through 8, who bind together in scrums, line up for lineouts, and are in most rucks and mauls.

Forward Pass -An illegal pass to a player ahead of the ball causing the ball to be awarded to the other team in a scrum.

Free kick -A kick, usually awarded for a minor penalty by the opponents.  A direct attempt at goal may not be made from a free kick (unlike a penalty) until an opponent touches the ball, a tackle is made, or the ball has been made dead.

Front Five -A common name for all of the front (props and hooker) and second row (locks) forwards. Also known as Tight Five.

Front row -The combination of two props and the hooker at the front of a scrum.

Fullback -The back wearing No. 15 who normally plays deep behind the backline. In offense the fullback is a dangerous attacking position hitting holes unexpectedly at pace, in defense the fullback has primary responsibility for covering all tactical kicks down field by the opposition.

Gain line -An imaginary line across the field at the point where the ball became dead. See dead ball.

Goal -A score of 3 points awarded for drop-kicking the ball over the opponents goal-post during play, or place-kicking it through on a penalty kick. The ball must pass between the goal posts and above the crossbar.

Grubber -A kick that bounces or rolls along the ground (similar to a squib kick).

Hooker -The front row forward wearing No. 2. The player is supported on either side in the scrum by props and is required to gain possession of the ball in the scrum by hooking or blocking the ball with one of his/her feet. The hooker will normally also be the forward who throws the ball into the lineout.

In-goal -The area between the try-line and the dead-ball line.

Injury time -Extra time added to the end of a half to compensate for time stoppage due to injuries.

Inside centre -The back that usually wears No. 12.

IRB -The International Rugby Board. The IRB is the ruling body for Rugby Union worldwide and has primary responsibility for setting and adjusting the laws of the sport and running the Rugby World Cup championships for 15s and 7s every four years.

Jumper -The player in a lineout who's responsible for jumping to catch or intercept a throw.

Kick-off -A drop kick taken from the centre of the field to begin a half.

Knock-on -Where a player drops the ball forward (toward the opponents goal line). The ball is awarded to the opponents in a scrum for an unintentional knock-on. The opponents are given a penalty kick from the spot for an intentional knock-on.

League -A version of rugby played normally with 13 players under different laws than Rugby Union. The two codes deviated over professionalism and are usually contentious towards each other.

Lifting -The act of lifting the lineout jumper into the air in order to more easily catch or intercept the throw.

Lineout -The method of putting the ball back into play after it has gone out of bounds. The two sets of forwards line up opposite each other (although backs may join in, so long as the numbers are equal); a player from one side then calls a play and throws the ball between the two lines.

Lock -Either of the two forwards normally wearing No. 4 and No. 5. Typically the largest players on the field, they have primary responsibility for being the power in scrums and securing the ball in lineouts. Due to their size, they are also normally powerful forces in all loose play, rucks, and mauls. Also known as Second Row.

Loose Forwards -Common names for the flankers and No. 8 in a forward pack.

Loosehead -The No. 1 prop in a scrum named so because his/her head is on the outside of the front row.

Mark

1)      The spot designated by the referee as the location for a set piece (e.g. scrum).

2)      A player may make a fair catch by catching the ball cleanly from a kick by the opposing side and calling "Mark!" He must have at least one foot on the ground behind his side's 22-metre line or within the in-goal area. A free kick is usually awarded from the spot of the catch, at the referee's discretion.

Match -A match is made up of two halves, usually 40 minutes long, plus injury time. Teams change ends after halftime break.

Maul -When a runner has come into contact with opponents and cannot advance the ball further, players may bind themselves into a maul. There must be at least three players bound. The maul ends when the ball is on the ground; when the ball or the player who had been carrying it emerges from the maul; or when a scrum is ordered. A maul is similar to a ruck, except that the ball is not on the ground.

Number 8 -The forward who wears the jersey with the No. 8. This player binds into the scrum normally at the very base between the two locks. His/her responsibility is to initiate attacks by the forwards from scrums or to provide a stable ball from the scrum for the scrumhalf.

Obstruction -Getting in the way of an opponent who's chasing the ball. Also called blocking.  Results in the awarding of a penalty to the opposition.

Offside -An infringement committed when a player crosses the gain line during a lineout, maul, ruck, or scrum before it has been completed, or when a player is in front of the ball while it is played by a teammate. A penalty is called if an offside player then plays the ball, obstructs or tackles an opponent, or is within 10 metres of an opponent waiting for the ball. The other side is awarded a penalty kick from the spot of infringement or a scrum at the place where the offending side last played the ball. See also accidentally offside.

Outside centre -The back that usually wears No. 13.

Pack -The eight forwards when they are bound for a scrum. It consists of three front row players, two second row players, and three back row players.

Penalty -Any number of infractions or violations which award the other team a kick.

Penalty Kick -An uncontested kick awarded to a team for a major infraction by the other team. The kick can be taken directly at goal and scores 3 points if successful. If the ball is kicked to touch, then the ball is awarded back to the team which kicked the ball out of bounds.

Penalty try -A try that is awarded because the opposing side committed a flagrant infraction to prevent an obvious try from being scored, or for persistent re-offending.  The score is awarded directly between the goal posts regardless of where the infraction occurred.

Pitch -The rugby field is a maximum of 100 metres long, from try-line to try-line, and 70 metres wide. At each end of the field is an in-goal area, no more than 22 metres long. The field is marked by a half-way line, two 10-metre lines and two 22-metre lines, and by two dotted hash marks, each 5 metres from the sideline and extending from goal-line to goal-line. There is a set of goal posts on each try-line.

Place Kick -A kick of the ball resting on the ground, placed in an indention in the ground, from a small pile of sand, or from a kicking tee. Place kicks are used for penalty kicks at goal or for conversion kicks after a try has been awarded.

Prop -Either of the two forwards normally wearing No. 1 (loosehead) or No. 3 (tighthead). Responsibilites are to support the hooker during scrums and 2nd rows during lineouts.

Punt -A kick on which the ball is dropped and kicked before it reaches the ground. A goal cannot be scored with a punt.  Usually used for gaining ground and field position.

Referee -The sole judge and timekeeper for a match.

Restart -The kick restarting play after a half or after points are scored.

Ruck -When a runner has come into contact with opponents and the ball has gone to the ground, players may bind themselves into a ruck. There must be at least three players bound. The ruck ends when the ball leaves the ruck and can be handled by a player who is not part of the ruck, or when a scrum is ordered. A ruck is similar to a maul, except that the ball is on the ground.  A player may use his/her hands to play the ball while it is in a ruck – doing so results in a penalty for the opposition.

Rugby -A football game in which the ball is kicked or carried forward down a field to score points either by touching the ball down beyond a tryline or kicking the ball through posts. The primary rule governing the game is that no pass to a player forward of the ball is allowed. Two codes of rugby are played, Rugby Union and Rugby League. All information at this site concerns Rugby Union. Union is normally played with fifteen players, but versions of the game featuring only seven or ten players is also popular. Football is quite ancient and has existed in most every cultural group through time. The current form of Rugby Football was first developed at Rugby School in England and thus the school provided the name for the sport.

Rugger -Colloquial name for the game.

Scrum -A formation used to restart play after a minor infraction such as a knock-on or forward pass. Forwards on each side bind and the two groups come together, with the front rows interlocking to leave a tunnel between them. The scrum-half (#9) of the non-offending team feeds the ball into the tunnel midway between the front rows. The hookers attempt to get the ball back by ‘hooking’ it with their feet, while the other players try to push or ‘drive’ the opponent backwards. The scrum ends when the ball is out of the tunnel and in possession of a player on either team.  As with a ruck, a player may not use his/her hands while the ball is in the scrum.

Scrumdown -The coming together of the scrum.

Scrumhalf -The player wearing no.9.  Acts as a link between the forwards and backs by passing ball won by the forwards at a scrum, ruck, lineout or maul to the backs who then attempt to advance it up the field.  Also responsible for putting the ball in a set scrummages.

Scrummaging -The process of setting and completing a scrum.

Second row -The two locks, when in a scrum.  See also, lock.

Sending off -The expulsion of a player from a match. The side has to play one person short. A sending off may result from a flagrant or malicious foul, or from repeated fouls.

Set phase (set piece) -First piece of play from a lineout, scrum or restart.

Sevens -A version of rugby with only seven players on a side, typically three forwards and four backs. A half is usually only seven minutes long as the game is played on a full size pitch.

Tackle -The act of grabbing a player who has the ball and bringing him to the ground.  All tackles must be below the shoulders and tacklers must wrap their arms around the ball-carrier.

Tag –Name given to a non-contact version of rugby in which flag belts are worn by players and removal of flags/tags from these simulate tackles.  The term is used within lesson plans to describe the action of touching another player in a warm-up game with a ball.

Tap-penalty -A penalty kick, on which the player taps the ball with the foot, then picks it up and passes it to a teammate.  Usually used to try and catch the opposition unawares.

Ten-metre line -One of the broken lines running across the field, 10 metres from the halfway line.

Tight Five -A common name for all of the front (props and hooker) and second row (locks) forwards. Also known as Front Five.

Tighthead -The No. 3 prop in a scrum, named so because his/her head is in between those of the opposition hooker and loosehead when the scrum is formed.

Touch -The term used in rugby to denote out of bounds.  The ball is said to be ‘in touch’ when it contacts or crosses a touchline, or when the player carrying the ball steps out of bounds.  The term is also used in a non-contact form of rugby where tackles are simulated by a two handed touch on the hips of the ball-carrier.

Touchline -A line that runs the length of the pitch and marks the side boundary.

Touch judge -An official located on the side of the field to mark the spot where balls go out of touch and to judge kicks at goal. The touch judge may also call the referee's attention to infractions.

Try -A score, worth 5 points, that's awarded when the ball is touched down by a player on the attacking side after it has been carried or kicked across the try-line. The scoring team is also awarded a conversion kick.

Try-line -A goal line, which extends across the field. The try-lines are a maximum of 100 metres apart.

Tunnel -The gap between the opposing front rows in a scrum or between the two lines of forwards in a lineout.

Twenty-two-metre dropout -A kick from the 22-metre line, used to restart play after a missed penalty kick or drop goal has passed the dead-ball line or been touched down by a defending player. The ball is kicked back to the original attacking side.

Twenty-two-metre line -One of the solid lines running across the field, 22 metres from the try-line.

Up and under -A tactical kick which is placed very high and shallow allowing the kicker and supporting players to easily run underneath it for recovery. The kick is intended to put heavy pressure on any opposition player attempting to catch the ball. Also called a Garryowen due to the Irish club which originated the play.

Webb Ellis Trophy -The trophy awarded the men’s champions of the Rugby World Cup 15s. Currently held by England.

Wing/Winger -Either of the two backs wearing No. 11 or No. 14. Each will normally stay on the same side of the back line they are on throughout the match and are typically expected to be the fastest sprinters in the side. Wingers also have key duties during defense helping the fullback cover kicks and counterattacking.

 Thanks to Andy Pilkington for the Glossary