A few months ago (my, doesn't time fly!), a colleague asked me to cover her classes for a day, and requested I teach a particular step. I then had to clarify exactly what she meant, because her name for the step was not my name for the same step, and I knew of at least one other name for it as well. Then there is the question of the arm frame/flow to go with it, is there a shimmy or anything else layered on it, is it done on the spot, travelling, turning, if so which direction, starting from where ...? Once you start to think about the variations, no wonder we want to name a step or a sequence/combination.
The issue of codified belly dance steps or moves raises its head from time to time in various fora, along with the questions, do we really need it, and if so, which language should be used? Ballet terms are mostly in French because of its development in the court of Louis XIV. Once you know the names of the steps, you can take a class elsewhere in the world and still follow the teacher setting the exercises.
For dancers who are keen to improve their dance, a standard, named set of moves to work on is indispensable as a basis for recording and teaching the moves and combinations, and for assessment. ATS and other Improvised Tribal Styles use names for the moves and combinations, although the same move may have small differences, depending on the format. The names are also used in tribal fusion, where you want to write something short which everyone recognises in the choreography notes. In ATS/ITS, you learn the combination and it goes into muscle memory. But the dance is improvised, so while you're following the leader, do you see a cue and think to yourself, 'Ah, this is a such-and-such'? I don't, but perhaps some dancers do.
I'm on the JWAAD personal development programme, and I like the way they have a standardised, basic set of moves. Whilst we may or may not use their names for the moves outside the JWAAD courses, at least they give us a common reference. Progress is monitored by assessing the quality with which the movements are executed, and since there is more to the dance than being able to do individual moves, the quality of your use of arms, spinning, musicality and flow is also considered. While I struggle with my isolations and don't feel I dance well when improvising to unknown music during my assessments, I prefer to be assessed on this relatively level playing field, which makes some allowance to age and physical limitations. Advancement is about a technical/biomechanical and effective ability to dance a standard set of more basic moves, rather than the need to demonstrate increasingly complicated moves such as backbends or a Turkish fold (i.e. kneeling with the knees apart and bottom of the floor, and then lying down), which become difficult, dangerous or just downright impossible with age. Older dancers may be able to dance extremely well and use their experience to bring expression to their dance, without necessarily being able to do floor work or other physically demanding moves.
I have a list of named moves, for any dancers who want one. It is scarily long, but useful as a tick list when trying to build a movement vocabulary. However, the more I tried to list and name belly dance moves in all their variety and permutations, the more I realised that belly dance is more than just a set of moves, it is a way of moving through the body, reflecting the music. There are some core moves, such as hip figure 8s, but they (and more complex, compound moves) can be broken down into slides, arcs and circles, undulations, twists and tilts or lifts and drops, which are the basis for the body core movement with step patterns, turns and arm shapes and flows.
There is a trap in thinking of dance in terms of a set of moves, even when broken down into core movements, and that is in thinking that if you learn the moves and some combinations, you can dance and that's all there is to it. It's good to have a toolbox of moves and combinations which you can use in your dance, but if you use only the same combinations over and over, regardless of the music or style of dance, it's like dancing-by-numbers. Differences in styles rely on small differences in moves and their qualities, nuances which are lost by using a sort of one-style-fits-all approach.
Even more of a trap is thinking that if you can't remember moves and combinations, you can't dance. Trying to remember moves and think about which to do next often kills flow and expression during improvisation. Posture, personality, flow and transitions and the use of dynamics are all part of the dance, but you cannot consciously think of them all while dancing. Instead of trying to remember moves, set some rules (or just guidelines) and let the music move you. The rules can relate to typical moves and dynamics for a style, or use the classical Egyptian formula of arms for ney flute, shimmies for qanun and oud, etc.
Most important of all is musicality. Listen actively to the music and dance to both the rhythm and the melody. The thing which makes the real difference is practice, practice, practice. So don't worry so much what moves are called, but break them down into their core components, look at the details, practise them, and when the music calls for it, let the music take over your body, let go and just dance!