There is a lot of associated terminology when talking about waves. It's handy to know what it all means if you want to start forecasting your own surf. If you are looking to increase your own general surf vocabulary, then take a look at the surfing terminology section. OK, let's get cracking.
The main wave features
This is the vertical distance from still water level to wave peak. (Approximately half the height of the wave)
The barrel is the hollow part of a breaking wave where there is a gap between the face of the wave and the lip of the wave as it curls over. One of the highlights for any surfer is catching a tube ride. See "Tube."
This is the measurement of water depth at various places in a body of water
These are the first small waves created when the wind blows on the sea. (i.e. baby swell)
Moderate local winds form little waves known as chop which can kill a good surf session. It's also know as "wind chop."
This is a wave that breaks along its entire length at the same time making it unsurfable. Closeouts can either be caused by a strong offshore wind or sea floor topography. It's also called "shutting down."
This is a swell line that looks like corduroy. See this corduroy swell picture that illustrates it perfectly.
The crest is the highest part of the wave above still water level. See also "Peak."
Crumble / Crumbly Waves
Waves affected by an onshore wind are said to crumble. The lip of the waves will "crumble" along the line and as a result spoil the waves for surfers.
Decay of Waves / Wave Decay
This is the decrease in wave height and increase in wavelength of a wave once it's outside the fetch.
When the wave comes into contact with an obstacle or barrier such as a breakwater, the energy of the wave is transmitted along a wave crest. Diffraction is the "spreading" of waves into the sheltered region within the barrier's geometric shadow.
Dumpy Shore Break
Waves that are breaking very close to shore in shallow water. They can be great fun to ride, but be careful not to break your board.
Fetch is the area of sea surface where the wind generates the waves / swell. It's one of the key facets of the quality of a swell and the size of the waves.
Fully Developed Sea
Waves that have reached the maximum size possible for fetch, wind speed and wind duration are referred to as being fully developed.
Grinder / Grinding Wave
A powerful breaking wave. "The waves were grinding along the reef"
Waves that have incredibly smooth faces due to the lack of local wind or a slight offshore wind. Have a look at this picture of a glassy Huntingdon Beach wave.
This is when the waves are no longer being affected by the winds that generated them, typically outside the fetch.
A "left" is a wave that breaks from left to right as you are looking from the beach.
A wave that has passed through the lineup and not been caught by a surfer.
The lip is the upper-most part of the breaking wave where a surfer will do maneuvers such as a floater.
Smaller than normal tides occurring when the gravitational pull of the sun and moon are at right angles to the earth.
In surfing terms this relates to the wind blowing from the shore. A ground swell mixed with offshore winds makes for cracking surf.
The opposite of offshore waves, these occur when the wind blows toward the beach, and as a result the waves lose their shape and crumble.
This is the highest part of the wave above still water level. See also "Crest."
This is the wave direction at the frequency at which a wave spectrum reaches its maximum.
Peak Period / Wave Period
This represent the period of time it takes for consecutive wave crests or wave troughs to pass a given point. The greater the wave period is the better the swell.
This represent the tendency of wave crests to become parallel to underwater contours as waves move into shallower waters. Waves moving in shallow waters move more slowly than waves moving in deeper water. Refraction can be seen where waves wrap round a point and their direction seems to change.
Refraction of waves
A "right" is a wave that breaks from right to left when viewed from the beach
Significant Wave Height
How significant are your wave heights? You are likely to have seen significant wave height on surf reports. The significant wave height is the average height of the one-third highest waves of a given wave group.
Waves being forced to bunch together as they enter shallower water slow down and are said to be shoaling.
See dumpy shore break.
These larger than normal tides occur when the gravitational pull of the sun and moon are combined in line. This is opposite to neap tides.
These are waves breaking near the shore. Tadaa!
This represents the area from the shore out to where the waves start breaking
Tides are an increase and decrease in sea level resulting from the moon's and, to a lesser extent, sun's gravitational pull.
This is the lowest part between two successive waves. It can also be considered the part between two successive waves below still water level.
The hollow part of a breaking wave where there is a gap between the face of the wave and the lip of the wave as it curls over. See "Barrel."
The steep, unbroken section of a wave, out in front of a surfer. Reason: it looks like a wall made out of water. You'll probably hear surfers talking about a wave "walling up".
Wave Direction / Swell Direction
This is the direction from where the waves approach. (Not the direction in which they are heading) If a surf spot works on a northerly, this refers to a northerly swell direction.
This is the distance between two corresponding points on successive waves. (i.e. the distance between two peaks)
This is the foamy part of a wave that has broken