Belly Dance technique may be divided into four basic types of movement:
Lyrical, Percussive, Locomotor, and Layered.

Lyrical (muscular) movements are characterized by a smooth flowing quality. The origin of the movements is in the muscles. Lyrical movements give the illusion of being purely muscular--the dancer appears to have no bones. Lyrical movements have a watery or wave-like quality, one movement flows into the next. They are often performed during a taximi or to slow tempo music, usually melodic. Lyrical movement can be arrhythmic (not following any specific meter).

Percussive (mechanical) movements are characterized by a sharp, exact, quality. Percussive movements are often performed during drum solos or to fast-tempo music. The movements should appear to be "mechanical" and precise. Percussive movements often use "locks" and stops. Percussive movements should always be executed rhythmically (on the meter of the song).

Locomotor movements are moving steps. They are all variations on the basic walk Many movements, either lyrical or percussive, can be turned into Locomotor movements by layering the movement onto a "walk".

Layering is an important concept in Belly Dance. Layering is the process of adding one movement to another to execute both simultaneously. For example: a percussive movement (the hip shimmy) can be layered onto a basic walk. The resulting movement is the Locomotor Movement shimmy walk.

Some layered movements may mix lyrical and percussive elements. Percussive movement can be layered onto lyrical movement (shimmy layered onto a hip figure 8) to produce a mixed effect.

Some movement combinations, while not strictly layering, may also produce "mixed" effects. A lyrical movement may end with a lock according to the musical phrasing to produce a dramatic effect.

Level Changes
Level Changes can be considered two ways:
1. as a variation of Layering
i.e. a hip shimmy is layered onto a grand plie--sometimes called a shimmy down
2. as an element of movement
i.e. dance movements can be executed standing, in releve, on the floor, etc.

Movements unique to Belly Dance:

Shimmy
a vibrato movement alternating up & down or side to side

Freeze
a tense, fast vibrato movement. Involves less mechanical movement and more muscular tension than the shimmy

Slide
An isolation movement on the horizontal.  Head may slide from side to side or front to back on a horizontal plane.  Chest may slide from side to side or front to back on a horizontal plane. Hips may slide from side to side or front to back on a horizontal plane.

Undulation
A bodywave moving either up or down the torso. A snake-like movement of the spine. Can be vertical or horizontal.

Infinity (or Figure 8)
The hips or ribcage trace a figure 8 or infinity sign. The hip infinity can be done either horizontally or vertically.

Head
Head slides, head rolls (from Zaar or Guedra trance dance)

Arms & Hands
Lyrical Movements:
snake arms, hand floreos, shoulder rolls.
The basic Snake Arms movement has several variations:
twisting snake arms, low snake arms, high snake arms, etc.
Poses and Positions:
Positions 1 - 5 modified for Near Eastern dance (see above illustrations)
Persian and Central Asian Arm Poses

Shoulders
Percussive:
Shoulder Shimmy (even time and triplet time), Shoulder drop.
The basic shoulder shimmy can be executed with one shoulder or both.

Lyrical:
shoulder rolls and twisting snake arms involve both shoulders and arms.

Chest
Lyrical Movements: lateral chest slide, chest circle, lateral chest Figure 8
(Figure 8s are also called Infinities).
Chest Circles have many variations including:  horizontal chest circles, vertical chest circles and diagonal chest circles (samba style).
Percussive Movements: Egyptian chest pop

Torso
Lyrical: Vertical Torso Undulation (also called camel or body wave).
The vertical torso undulation usually initiates in the chest and rolls down through the hips. A "reverse" may also be executed initiating in the hips and rolling up through the chest.
Lateral (Sideways) Torso Undulation.

Stomach:
Belly roll, reverse belly roll, belly flutter, belly pops and belly drops.

Hips
Lyrical Hip Movements:
Hip Circles. The Hip Circle movement has 3 basic directions:
horizontal hip circle, vertical hip circle, and diagonal hip circle.
Hip Circles also come in 3 basic sizes:
Large hip circles (Egyptian Style), Medium Hip circles (Arabic Style) and small hip circles (similar to Samba or Tahitian Style).
Hip circles may also be executed as half-circles or one-leg hip circles.
Figure 8s (also called Infinities or Mayas).
The hip Figure 8 has 4 basic types:
Horizontal front, horizontal back, vertical up, and vertical down.
Figure 8s may also have a mixed nature, neither purely horizontal nor purely vertical, but a mixture of both.
Figure 8s may also be executed with one hip only.
Hip Undulations (called an Arabic in Salimpour and Nericcio formats).
The Hip Undulation is often layered onto a walk.

Percussive Hip Movements:
hip snap, hip drop, hip twist, hip locks, and hip shimmy (even time or triplet time).
Even Time Shimmy denotes one movement per one count of music--the count would be 1-2-1-2 in 2/4 time (up-down-up-down). Even Time shimmys may be done double-time (twice as fast) or half-time (slower) but the movement count is always even with the meter (beat of the music).
Triplet Hip Shimmys may be done "up-down-up, down-up-down, up-up-down" etc. There are many variations. Triplet is used according to standard musical terminology:  it denotes 3 movements done to 2 beats of music
(Count 1&2 3&4 in 4/4 time).
Similar patterns (up-down-up, etc.) could be done to 3/4 or 6/8 time music yielding a 3/4 or 6/8 shimmy.  
Note:   There is some confusion over the term 3/4 shimmy.  Naming conventions used here attempt to resolve the confusion by basing names on the time signature (count) of the music.
I.E.. all 2/4, 4/4, or 8/8 time signatures will take a triplet shimmy
3/4 music will yield a 3/4 shimmy.

Locomotor Movements:
Beledi Walk, Shimmy Walk, Grapevine Step, Ghawazee, Algerian Walk, Double-Algerian, Twist walk, Persian, Saidi Hops, & many other variations on the basic walk.

Turns:
Axis Turn (a pivot turn onto which a movement is layered.}
Dancer turns on her own axis. Could be described--front side back side, around the world, etc.  Hip drops, hip circles, hip undulations etc. are commonly layered onto an Axis Turn.
Chaine Turns (shen-ay = chain) Sequential turns moving across the floor
Spins--sometimes called paddle turn. Dancer spins in one place
Barrel Turns--a spin spotting the floor. See the movie Latcho Drom

advanced / level 3 study guide:
poses, floorwork, balancing props