Salsa is a dance form with origins from the Cuban Son (circa 1920s) and Afro-Cuban dance (specifically Afro-Cuban Rumba. It is generally associated with the salsa music style, although it may be danced under other types of music with an 8-count rhythm.
These salsa styles are made up out of different step patterns, different
timing of steps, particular movement on the dance floor (for example:
slot, circular), dancer preference of turns and moves, attitude, dress
code, and others.
In many styles of Salsa dancing, as a dancer changes weight by
stepping, the upper body remains level and nearly unaffected by the
weight changes. Weight shifts cause the hips to move. Arm and shoulder
movements are also incorporated. The Cuban Casino style of Salsa dancing
involves significant movement above the waist, with up-and-down
shoulder movements and shifting of the ribcage.
The arms are used by the "lead" dancer to communicate or signal the
"follower," either in "open" or "closed" position. The open position
requires the two dancers to hold one or both hands, especially for moves
that involve turns, putting arms behind the back, or moving around each
other, to name a few examples. In the closed position, the leader puts
the right hand on the follower's back, while the follower puts the left
hand on the leader's shoulder.