Ergometer: A rowing machine (rowers call it an "erg") that allows the user to simulate the rowing motion and measure his or her rowing capacity.
Coxswain (pronounced COX-n): The person who steers the shell by a rudder and is the on-the-water coach for the crew.
Oars: They not only propel the boat through the water but act as balancers. The shaft varies in length somewhat, but sweep rowers' oars are longer (12 to 13 feet) than scullers' (9 1/2 to 10 feet).
Scull: A rowing boat in which each person has two oars.
Shell: Generic term for all boats, including sculls. However, all shells are not sculls.
Sweep Rower: A rower using one oar. Sweep rowers come in pairs, fours, and eights. "Eights" are always coxed; pairs and fours may or may not be.
Scullers: People using two oars. One person with two oars is a single, two people with two oars is a double, four people with two oars each is a quad.
Adapted from 'The Regatta Watchers Guide,' available from US Rowing.