Below is a list of some common rugby terms and lingo you are likely to hear thrown around the pitch (you'll find out in a second).
Backs- The group of players normally numbered 9 through 15 who do not participate in scrums and lineouts, except for the scrumhalf.
Blindside- From a set piece (lineout, scrum), ruck or maul it is the short side of the field.
Break Down- The term 'break down' usually refers to the ruck or tackle situation.
Cap- Anytime a player plays in a sanctioned match he/she is technically awarded a cap for the team he plays for in that match. This is most commonly practiced with international teams (e.g. if someone has 51 caps for their country they have played in 51 sanctioned test matches for that team).
Conversion- After scoring a try, the scoring team attempts to kick the ball through the uprights from any point on an imaginary line that runs the length of the field through where the ball was touched down. In rugby union the conversion is worth 2 points.
Drop Goal- A drop goal is worth three points and can be scored at any time during a game by simply kicking the ball through the uprights after it has been dropped and touched the ground.
Forwards- The group of players normally numbered 1 through 8 who bind together to form the scrum andlineouts.
Front Row- The common name for the Prop/Hooker/Prop combination at the front of a scrum.
Garry Owen- A kick which is high in the air, normally short enough that you can pressure the receiver or can collect it yourself.
Gate- This is the term used to describe the imaginary place at the back center of a ruck or maul where players must engage at to be considered joining the ruck or maul properly.
Grubber- A kick of the ball which causes the ball to bounce and roll along the ground with the intention of being recollected. Often used to attack with on offense.
Knock On- Losing, dropping, or knocking the ball forward from a player's hand resulting in the ball being awarded to the other team in a scrum.
Lineout- The setplay restarting play after the ball has been taken out or kicked to touch.
Loose Forwards- The combination of the flankers and eight man.
Mark- A location on the pitch designated by the referee as the location a scrum should come together. You can also call 'mark' when catching a ball within your team's 22. As you are catching the ball you call 'mark' and you get to take a kick from the spot you called the mark. You cannot call mark on kickoffs or restart kicks unless its a 22 meter drop out.
Maul- A maul occurs when the player with the ball is wrapped up, but not taken to the ground and players from both sides bind together to push the ball forward (or backwards in the defenses case).
Offsides- During rucks, scrums, lineouts, and mauls an imaginary line is present over which any player crossing before the set piece is completed committs a penalty.
Openside- From a set piece (lineout, scrum), ruck or maul it is the big side of the field.
Pack- Another common name for all the forwards.
Penalty Try- The awarding of a try due to a flagrant violation by an opposing side that prevents an obvious try from being scored.
Pitch- The field.
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.
Restart- The kick restarting play after a half or after points are scored.
Ruck- Typically after a runner has been tackled and released the ball players will both rush to the ball to try and gain possession of it. A ruck is formed when any combination of three players from both teams bind together over the ball to try and push over and gain possession.
Second Row- Can refer individually to either of the two forwards normally wearing No. 4 and No. 5 (e.g. "he is a second row") or can refer to both players together (i.e. the second row in the scrum).
Set Piece(s)- A general term referring to either the scrum, lineout or both.
Scrum- A scrum occurs when the ball is put back into play after an infraction such as a knock on and each team's forwards lock together in a set manner, trying to position the scrum so that each team's hooker can kick or "hook" the ball back to the number 8 and gain possession for their team.
Strongside- Same as the openside (see above).
Touch- Out of bounds line. You will hear people say "kick for touch" which simply means kick it out of bounds.
Touch Judge- An official posted on each side of the pitch to mark the spot where balls go out of touch and to judge kicks at goal.
Try- The rugby equivalent of a touchdown in American football. To do it you have to actually touch the ball in the try zone. In rugby union a try is worth 5 points.
Try Zone- The rugby equivalent of an endzone in American football. This is where you have to touch the ball down to score in rugby.
Up-and-Over or Chip Kick- Similar to the Garry Owen, the up-and-over or chip kick tends to be kicked just high enough to go over the defense with the explicit goal of the kicker collecting the ball once past the defense. There is no technical difference from a Garry Owen, only a slight semantic difference (if that even exists).
Weakside- Same as the blind side (see above).