Diagram of an 8+

Parts and Orientation Of The Boat
Shell Is another name for the boat and is used interchangeably.
Port Left side of the boat, while facing forward, in the direction of the movement.
Starboard Right side of the boat, while facing forward, in the direction of the movement.
Bow The forward section of the boat. This part of the boat crosses the finish line first. 
Stern The rear of the boat; the direction the rowers are facing.

Bow Ball A small rubber ball attached to the bow of each shell. Used as a safety device and for determining which crew crosses the finish line first during a close race.
Skeg/Fin and Rudder The fin attached to the keel of the shell that helps stabilize and maintain a straight course. The rudder attaches to the skeg and is controlled by either the coxswain to steer a sweep boat by attached cables or by the toe in a sculling boat.
Deck The part of the shell on top or the bow and stern that is covered with fiberglass or thin plastic.
Gunwales The top rails of the shell. Pronounced - 'gunnels'
Hull The body of the shell.
Keel The center line of the hull.

Rigger The triangular shaped metal device that is bolted onto the side of the boat and holds the oars.
Rib The u-shaped structures in the boat that the hull and riggers attach to. 
Oarlock The u-shaped lock at the end of the rigger that attaches the oar to the shell. The oarlock allows the rower to rotate the oar between the squared and feathered positions.
Gate The bar across the oarlock that keeps the oar in place.

Toe Sculling boats may have a steering device. The bow or stroke seat can steer the rudder by changing the direction of their foot.
Foot Stretcher The adjustable footplate with built in shoes which allows the rower to adjust their position in the shell relative to the oarlock.
Seat Molded seat mounted on wheels that the rower sits on. The seat rolls on tracks which allow the rower to generate power with their legs.
Tracks/Slides Rails that the rowers rolling seat roll on. Also called slides.

Parts Of The Oar
Oar Device used to drive the boat forward. An oar consists of several parts, in order from rower to water: Handle, shaft, sleeve, collar, shaft, blade. The oar attaches to the boat at the oarlock.
Handle Part of the oar that rowers hold on to during each stroke.
Shaft The part of the oar between the sleeve and the blade. Comprises the majority of the length of the oar. Also called the loom.
Sleeve A thin piece of plastic around the oar that keeps the oarlock from wearing out the shaft of the oar.
Collar A wide collar on the sleeve of the oar that keeps the oar from slipping through the oarlock. Also called a button.
Blade The hatchet or spoon shaped end of the oar.
Outboard The length of the oar measuring from the bottom to the tip of the blade.
Inboard Length of the oar measuring from the button to the handle.
Button A wide collar on the sleeve of the oar that keeps the oar from slipping through the oarlock. Also called a collar.
CLAM Acronym for Clip-on Load Adjusting Mechanism. A CLAM is a device that snaps on and off the sleeve of an oar to quickly adjust the inboard rig. Typically by 1 cm per CLAM.

Types of Oars
Hatchet The modern and current oar blade that is rectangular or hatchet shaped.
Tulip/Macon/Spoon The traditional u-shaped blade. 

Racing Terminology
Head Race Type of race where crews start in a single file line and race for time. Longer than sprint races, head races range from 4k to 10k and are usually run on rivers during the fall season.
Sprint Race Type of race where crews race side by side in lanes over 2000 meters. In the US, this is the standard race and the season is the spring and summer.

Repechage A second chance heat at a regatta to ensure that all crews have two chances to advance. These races are for all crews that didn't qualify in their heat. French word meaning 'to save' or 'second chance'.
Grand Final Finals at a regatta for places 1 through 6.
Petite Final Finals at a regatta for places 7 through 12.
Third Final Finals at a regatta for places 13 through 18. 

Start The beginning of the race. Crews will have a specified starting sequence of strokes to get the shell up to speed as quickly as possible. Stroke ratings during a start sequence range from the low 40s to the high 50s.
Sprint The last portion of a race. Usually the last 250 meters of the race are run at a maximum stroke rate in an attempt to get to the finish line first.
Bow Number A card attached near the bow of each shell that identifies which lane the crew is assigned to.
Power 10 A call by the coxswain for the crew to row the next 10 strokes at maximal effort in an attempt to increase boat speed and take water on the opponent.
Seat Race A coach's tool for comparing two rowers. Two boats race against each other once. One rower from each boat switches positions and the two boats race again. Relative performance in the two races is used to compare the abilities of the two rowers.
Stakeboat The small anchored boat that is used to hold the shells in place at the starting line. 
Launch Motorboat used by rowing coaches and referees.
Buoy Colored flotation devices that mark lanes and other various areas of the race course. Also used for marking hazards.

Classifications Of Rowers
Novice Any rower during their first season of competition.

Classifications By Age
Junior A Junior is a competitor who in the current calendar year does not attain the age of 19, or who is and has been continuously enrolled in secondary school as a full time student seeking a diploma. A competitor thus ceases to be a Junior after December 31 of the year of his or her 18th birthday, or of the year in which he or she completes the 12th grade of secondary school, having been a full time student, whichever is later. 

Master A Master is a competitor who has attained or will attain the age of 21 during the current calendar year. A competitor’s age is determined as of December 31 of the current calendar year, rounded down to the highest contained integer. A competitor thus becomes a Master on January 1 of the year of his or her 21st birthday. A Masters crew shall be comprised exclusively of Masters rowers, but the coxswain need not be a Master. 
(From the USRowing Rules of Rowing Rule 4-104)

Classifications By Weight
Lightweight vs Open Weight  An athlete of any weight can enter the open categories, although the average woman in an open race will approach 6' in height and an average open weight man 6'6". Lightweight men cannot weigh more than 160 pounds and the average weight in the entire boat cannot exceed 155 pounds. Lightweight women cannot weigh more than 130 pounds and the average weight in the entire boat cannot exceed 125 pounds. 

Types Of Rowing
Sculling In sculling, each rower uses two oars (one in each hand) to move the boat.
Sweep In sweep rowing, each rower uses on oar and is paired with another rower of the opposite side. Sweep boats usually have a coxswain. Pairs and fours can be without a coxswain (coxless).

Types Of Boats
Octuple (8x) A sculling boat for eight rowers.  Must have a coxswain
Quad (4x) A sculling boat for four rowers.
Double (2x) A sculling boat for two rowers.
Single (1x) A sculling boat for one rower.
Eight (8+) A sweep boat for eight rowers and a coxswain (diagram above)
Four (4+ or 4-) A sweep boat for four rowers. Can be with or without a coxswain.
Pair (2+ or 2-) A sweep boat for two rowers. Can be with or without a coxswain.
Straight A coxless sweep shell. Only for a pair or a four. Referred to as a 'straight four.'
Bowloader Refers to a type of boat (usually a four) where the coxswain rides lying down beneath the bow decking. Most racing fours are bowloaders.

Positions Of The Rowers In A Boat
Seat Number Refers to the rower's position in the boat counting up from bow to stern. In an eight these are counted as the bow seat being 1, then 2, 3, 4, 5, 6, 7, and finally 8 in the stern. 8 seat is also referred to as 'stroke' seat.
Bow Pair The pair of sweep rowers in bow of the boat. This would be seats 1 and 2 in an eight or a four. The bow pair has the most effect on the set of the boat.
Stern Pair The pair of sweep rowers in the stern of the boat. This would be seats 7 and 8 in an eight or seats 3 and 4 in a four. The stern pair is responsible for setting the rating and rhythm for the rest of the crew.
Coxswain/Cox Person who steers the shell and coaches for the crew on the water in a sweep boat.

The Rowing Stroke
One complete cycle of the catch, drive, release, and recovery.  The term Stroke is also the stern most rower in the boat who is responsible for setting the stroke rating and rhythm of the crew.
Catch The moment the blade enters the water and initiates the drive of each stroke.
Drive Portion of the stroke that propels the boat through the water. The drive starts at the catch and ends with the release. The main power from the drive is generated by the rower's legs pushing off the footstretchers.
Finish/Release The end of the drive when the rower removes the oar from the water and then feathers. Also called the release.
Recovery The portion of the stroke after the rower releases the oar from the water and returns to the catch position.

Square The act of rotating the oar prior to the catch so that the blade is perpendicular to the water. The opposite of the feathered position.
Feather The act of rotating the oar at the finish so that the oar's blade is parallel to the water during the recovery. The opposite of the squared position.
Pitch The angle between a squared blade and a line perpendicular to the water's surface. The standard pitch is around 4 degrees.
Backsplash The water thrown back toward bow by the oar's blade as it enters the water during the catch. A proper catch should throw a small amount of water.

Crab Occurs from a blade work error where a rower is unable to properly remove their oar from the water. A crab can slow down or even stop the boat. In extreme cases a crab can eject the rower from the shell.
Digging Rower error when the blade of the oar goes deeper in the water than it should, slowing the boat down.
Air Stroke A rower error where the oar's blade is not completely in the water. This results a complete lack of power and a lot of splashing.
Skying A rower error where the rower drops their hands just prior to the catch. This causes the blade to move higher off the water and will disrupt the set of the shell.
Missing Water A rower error where the rower begins the leg drive before the catch has completed.
Washing Out A rower error when an oar comes out of the water during the drive and creates surface wash. This results in a reduction in speed and can disrupt the set of the boat.

Split The amount of time it would take a rower or crew to complete 500 meters at their current pace. This can be applied to both a crew on the water or a person on an erg.
Rating/Stroke Rate The number of strokes per minute taken by a crew. During the body of the race a crew will maintain a rating in the mid to high 30's.
Ratio The relationship between the time taken between the drive and recovery portions of the stroke. A good ratio will have about twice as much time taken during the recovery as the drive.

Swing The feeling in the boat when all rowers are driving and finishing their strokes together.
Set Refers to the balance of the boat. An unset boat will lean to either port or starboard.
Settle Refers to a down shift in stroke rate after the start of a sprint race. Crews use the settle to get to their base stroke rating they will row the body of the race.
Run The distance the shell moves during one stroke. This can be seen by looking at the distance between the puddles made by the same oar.

Rush A rower error where the rower moves toward the stern during the recovery before the rest of the crew. This increases the amount of check during each stroke.
Check The reverse momentum resulting from the crews body weight moving toward stern during the recovery. Check is unavoidable but can be minimized through proper technique for optimal speed.

Rowing Commands
Way Enough
 Cox or Bow seat call to have all rowers stop whatever they are doing. Sounds like "way nuff".
Ready All, Row Cox or Bow seat call to begin rowing.
Check It Down Cox or Bow seat call for all rowers to drag their oar blades through the water perpendicularly, slowing or stopping the boat.
Let It Run Cox or Bow seat call for all rowers to stop rowing and to pause at the finish, letting the boat glide through the water and coast to a stop. Used as a drill to build balance.
One Foot Up….And Out Command for exiting the boat. The outside hand holds the oar(s) the inside hand holds the gunwale to the dock. The inside foot is placed on the dock, outside foot steps onto the step strip, body shifts forward and up to standing position on their inside leg., then step out of the shell onto the dock .

Other Terms and Equipment
Coxbox A coxswain's portable voice amplifier. Also has timing and stroke rating measurement capabilities.
Ergometer Also called an 'erg'. The indoor rowing machine used for land based fitness training.
FISA Acronym for Federation Internationale des Societes d'Aviron. International governing body for the sport of rowing.
Megaphone Device used by coaches to communicate with the crew.
Speed Coach A keel mounted impeller that transmits speed to the coxswain or coach.
Sling Portable folding boat holders. Two are required to hold a boat and are seen frequently at regattas.
Piece A practice term used to signify an specific interval during a workout. For example, "The third piece of the 5 by 5 minutes was our best."
Pogies A type of glove with holes on the ends which allow the rower to row with bare hands on the handle.
Rig Term used to describe how the boat is set up.
Shooting Slide A rower error when the rower's legs drive the seat toward bow without bringing the load of the water with them through the torso and shoulders.
Puddles The disturbances in the water made by the blade during each stroke.
Spacing/CoverThe distance between the 2-seat's puddle on one stroke and the stroke seat's puddle on the following stroke. The greater the distance, the more speed the crew has.
Swamped Swamping occurs when a shell takes on too much water from rough conditions and is no longer rowable.
Understroke Rowing at a lower and more efficient rating than your opponent.
Wash Refers to the wake given off of a shell.