Scudding: making the kite drag you along the beach on your feet.
Shaper: is a board maker, who designs and constructs boards.
Sheeting out/in: Sheeting out decreases the tension on the lines that lead to the edge of the kite to decrease the angle of attack (AOA) and lower the kite's power (Depowering the kite). Sheeting in has the opposite effect (Powers the kite up). Sheeting is not possible on a 2 line kite.
Shroud Lines: Bridle lines are sometimes called shroud lines.
Side-Shore: when the wind is blowing parallel to the shore line (along the beach). This is most desirable for kitesurfing.
Sine wave: flying the kite up and down at the edge of the wind window to generate more power with apparent wind.
Sining: Sining the kite means moving it in a sine wave pattern (up and down) to generate apparent wind and increase it's power.
Sleeving: short protective sleeve which covers the ends of a line and helps to preserve strength and prevent wear.
Slogging: moving along slowly with the board not fully planing.
Snap shackle: a metal shackle that can be opened by pulling on a release mechanism.
Span: the kite width, the size of the kite measured at right angles to the wind.
Spar: the sticks used as the frame of a kite. A batten is a spar.
Spectra: Also known as Dyneema in Europe. It is the standard for flying lines. It is slippery and will allow multiple line wraps without loosing kite control.
Spinout: when a board's fins lose "grip" on the water or stalls, causing the tail to slide sideways.
Splice: the place where two lines are joined together. A splice usually refers to a smooth join of two lines without using a knot. The end of one line is interlaced or runs through the core of another.
Spreader bar: the metal bar that is on the front of a kiters harness. It usually has a hook for holding the harness line or chicken loop.
Stall: Air is said to stall when it becomes detached from the surface it is flowing along. A stalled kite loses lift and falls from the sky. There is also a back-stall where the back lines of the kite are too tight. The kite begins to create lift in the opposite direction and flys backwards from the sky. This is a common mistake for beginners.
Starboard: The right side of a boat, from the perspective of a person looking forward. The opposite of port.
Starboard tack: Sailing on a tack with the wind coming from the starboard side (right side).
Stretch: the amount a line momentarily lengthens when pulled. Spectra has very low stretch, kevlar has slightly more, nylon has a lot. Stretch affects responsiveness and size of control movements.
Struts: term used to refer to the inflatable battens in an inflatable kite. Inflatable kites normally have 1-7 struts.