single knee hang-knee hang with a single knee.

single toe hang-toe hang with a single foot (not a single toe!).

skinning the cat-from hanging beating up and going straight through so hanging with arms pulled up behind you. Can then let go with one hand and turn back to usual hang.
sleeping beauty-doubles move: base sits on bar, flyer begins hanging by hands from right side of the bar, both facing out to audience. Flyer hooks right knee on base's left flexed foot, then places neck on base's right flexed foot. Flyer straightens both legs, and pushes hips up to make sure their body is straight, and both style. This is a nice trick because it gives the image that the flyer is lying across base's feet.

spotter-person at the safety lines.

star-x-shaped position formed from standing. Lift up and push ropes out with feet above velvets, holding ropes as high as possible with hands.

straddle-hanging under bar, hips up, legs wide, hands close together, crotch close to hands.

suicide-falling face toward the net (just turning before landing back toward the net).

swinging trapeze bar-a special trapeze bar used for swinging trapeze acts, there are usually small cylindrical or spherical weights at each end of the bar.