Definition from Wiktionary, the free dictionary
This index lists ASL signs that begin with the dominant hand making the “S” handshape.
“S” at the forearm
“S” in front of the shoulder
“S” in or beside the space in front of the torso
- “A” — with the thumb on the radial side of the index finger
- “T” — with the thumb under the index finger, thumb tip protruding between index and middle finger
- “O” — with the fingers and thumb more open to form a circle