Translatory Wave
A wave in which both the wave form and water move forward. A breaking wave is considered to be in a "Translatory" state as the water particles are significantly projected forward with the energy.

Tri-fin
A three fin surfboard setup - one large and two smaller fins.

Tripping
A person that's acting or being really sketchy.

Trim
A state in which the surfer and board travel across a wave face at precisely the speed needed to maintain position on the wave, without turning. Trim speed is a fundamental "go-to" for beginner surfers and super-skilled pros alike.

Tropical Cyclone
A warm-core cyclone, originating over tropical or subtropical waters, with a closed surface wind circulation around a well-defined center. The associated maximum sustained surface wind speed will range from 34 knots to 63 knots (39 to 73 mph). Ocean water temperatures need to be at least 80 degrees Fahrenheit to maintain the development of the cyclone, which is the extraction of heat energy from the ocean and heat export at the low temperatures of the upper troposphere.

Tropical Depression or Disturbance
A warm-core cyclone, originating over tropical or subtropical waters, in which the maximum sustained surface wind speed is 33 knots (38 mph) or less.

Tropical Storm Warning
A warning issued by the National Hurricane Center (NHC) that winds within the range of 34 to 63 knots (39 to 73 mph) associated with a tropical cyclone are expected in a specified coastal area within 24 hours or less.

Tropical Storm Watch
An announcement for specific coastal areas that tropical storm conditions are possible within 36 hours.

Tropical Wave
A trough, disturbance, or cyclonic curvature in the trade-wind easterlies originating over tropical or subtropical waters. Tropical waves are the first sign of possible future tropical cyclone development.

Trough
The lowest part of a wave as it begins to break. Or in deep water, the middle or lowest area between two wave crests.

Trunkable
When the ocean water temperature is warm enough to surf in trunks alone.

Tsunami
Commonly (and incorrectly) known as a tidal wave, a Tsunami involves long period ocean waves generated by earthquakes and other geological or tectonic disturbances below sea level. Tsunamis can travel at speeds of up to 500 knots through the open ocean. While they may be of low height in deep water, the shoaling process as they approach land can increase the tsunami to heights of over 35 feet or more in bays or other restricted areas.

Tube
See barrel.

Tube Ride
To ride behind or under the breaking curl of the wave.

Tubeage
Tubed, Barreled, Green Room, Shacked, or Bowled.

Tubesmith
A person that is unsually adept at spending time in the shack. A tube riding specialist.

Tubeular
When waves break like a barrel. Also '80s for something that is really cool.

Tuck and Run
To crouch low and drop into a tight barrel as you race down the line.

Tucked edge
A rail design popularized in the late 1970s in which a "soft" or rounded rail is finished at the bottom with a slightly angled edge, providing bite and release.

Turd Burglar
One who sits just inside the lineup and seems to be in the best position to pick off waves that other surfers are paddling for.

Turn and Brun
To turn around quickly and catch a wave that comes up quick.

Turtle
A paddling maneuver to help reduce resistance when paddling through whitewater, by rolling the surfboard upside down (with the fins up), and then holding on to the rails of the surfboard while underwater as the whitewater passes overhead. Used especially with longboards because the board's increased flotation makes duckdiving (the preferred method) difficult.

Two-wave hold down
During a radical wipeout, to be held under water for two successive waves. Usually only happens in large surf with very foamy conditions which make it difficult to swim to the surface. The actual time underwater may only be about 30-40 seconds long but seems like an eternity if you're the actual surfer being held down and fighting to rise to the surface.

Twazark
Someone who is really bent.

Twinfin
Two-fin surfboard design with a long and fascinating history; identified most strongly with four-time world surfing champion Mark Richards, who rode a twin in most of his contest successes outside Hawaii. The twinfin combines drive with release to create a very free design, which can be hard to control.

Twinzer
Four-fin surfboard design created by Will Jobson of California in 1990; adds control to the instability of the twinfin design.