Gravity wave - wave action caused by the swimmers' bodies moving through the water. Gravity wave move down and forward from the swimmer, bounce off the bottom of the pool and return to the surface in the form of turbulence. Gutter - the area at the edges of the pool in which water overflows during a race and is recirculated into the pool. Deep gutters catch surface wave and don't allow them to wash back into the pool and affect the race. Official - an judge on the deck of the pool.
Various judges watch the swimmer's strokes, turns and finishes or are timers.
Lanelines - the dividers used to delineate the individual lanes. These are made of individual finned disks strung on a cable which rotate on the cable when hit by a wave. The rotating disks dissipate surface tension waves in a competitive pool. Long Course - a pool configured for swimming with a 50 meter long racing course. World Records may be set in long course and short course competition.