We can almost start a new topic on “a list of confusing words in yoga”!
Taking this opportunity, let me collect some of the words that are really confusing to me. There was a time when I thought they’re confusing just because of my poor English. But let’s examine them. I’m sure there are many different definitions among you (if you ever have a definition or at least a rough meaning in mind before you use them!). The miracle is that yogis(and other spiritually-inclined people) keep their (our) discussions going for such a long time; and the price is a poor quality in the discussions and thus the conclusions. An even more severe and prevalent problem is that spirituality seems almost never reach people with a clear and rigorous mind, since discussing yoga with such vague terms make it looks more like religion and imaginations rather than actual experiences.
Here is a partial list of such words. If anyone feels appropriate and helpful, may be we can start a new topic 
Energy–
Related words: vibrations
What is that, really? Certainly not “energy” as in Physics. Do you mean a subjective feeling of “something” (just as when you’re having sex)? Or a sense of well-being and strength which will allow you to run 42km or read 10 books in a row? Kundaini? prana?
It’s ok for you to use “energy” to mean anything. But problems arise when you switch the meaning with the same word. If you (or your audience) are a “verbal” person who tends to use words for reasoning, such “double meaning” can impede your reasoning power by extending your conclusions to something you don’t have, and probably wrong. In particular, please don’t think you work the same way as an atomic bomb just because the word “energy” appears in physics texts.
Powerful (usually in “powerful practices/exercise”)
“This practice is very powerful” is certainly something we hear very often when learning a new yoga practice. I wonder whether there is any powerless practices! 
For this reason, this phrase soon lose it power on me : it really sounds meaningless!
Actually, it could be a helpful word if defined properly. But notice now different the following possible meanings of “powerful” are; and how often the word are used (and interpreted) without an awareness of which meaning it carries in that context.
a) The practice shows its effects quickily.
b) The practice plays an important role in your path to enlightenment.
c) The practice is a follow-up of some other practices, the series of which will lead you to enlightenment.
d) the practice give you physical strength/endurance.
e) the practice give you mental strength.
f) the practice is powerful in its pyschological effects because of its highly mythologized history (sorry to add this, but I think this is true in certain practices, particularly in certain Qi Qong traditions here in China. I’ll support my thoughts if necessary)
Enlightened
In this case, the vagueness seems to be acceptable. However, I would still like to know why certain people can say so conclusively that certain guru-like person is enlightened. It must due to some of your observations about them. In other words, if there are no external expressions of being enlightened, it makes no sense to say someone is enlightened (although much easier to say who’s not). So what are those expressions? Are you sure they can’t be faked?
Alvin
Hi Alvin,
This is an interesting topic about “confusing words in yoga”. I disagree with the strength of the statement above. I know several people with a clear and rigorous mind who are into spirituality. (And, how do we define spirituality?) However, there may be relatively less people into spirituality who have a clear and rigorous mind. An explanation could be that those who have a clear and rigorous mind tend to rely on this capacity as a strength in life, as a way to seek truth through logic and reason, and be less inclined to seek other avenues of truth, like spirituality.
If energy is used to describe phenomena outside of the physical world, then I think it’s still appropriate to use the term as it is defined in the dictionary: as “the potential for causing changes”.
About “powerful”. Most humans tend to seek the easy way, not having to elaborate, therefore using words like “powerful” as a shortcut to express something that has a considerable effect on something else.
Hi,
Energy— did not Einstein state that all mass is electrical energy? This is energy in the terms that yoga uses it just as in healing etc.
L&L
Dave
[quote=“weaver”]
I like very much to practise Tai Chi/Qi Gong.
Some people may mythologise the teachings/practices,
I don’t think that I myself do this, anyway, the practice
is powerful for me (as is yoga), both have effects on me.
The word powerful for me here means: gaining energy,
balancing energy, developing the nervous system,
developing my capacities.
(And by the way Alvin, my post is not meant critisizing you
in any way, it is meant encouraging to keep posting 
)
Alvin,
the best ‘translation’ I can give for ‘energy’ in the sense it tends to get used in yoga, is ‘a nervous-system dynamic’. Well, that’s pretty vague, but some more can be said…
It seems to me that our nervous-system is constantly switching and gating, and, while the whole thing is extremely complex, there are certain gross patterns. One thing is that at any time we have a sort of internal posture, which is our mental and emotional state; our internal posture reflects both our thoughts and processes, and also the thoughts and processes that are likely from our current state. Certain gates are ‘closed’ making certain pathways unlikely, others are open, making other pathways likely.
The word ‘energy’ is used to mean this internal posture, and/or also the shifting of internal posture.
So we can speak of someone with ‘loving energies’ or ‘angry energies’ or ‘needy energies’ or ‘grasping energies’ etc.
The posture itself is changing constantly, by events and thoughts. ‘Energy’ (internal posture) is expressed heavily in body-language (I mean body-language to include facial expression, tone of voice, movement and gestures). A drama-director will ask for a certain ‘energy’ from an actor. Really, they want the body-language that seems to go with that ‘energy’, or internal posture.
I hope that helps. It’s vague in its own way too, but a certain amount of vagueness is inevitable.
I’m sorry to say that this is a typical example of the confusion I’m refering to. Simply “stating” something means nothing until you make sense of it; and thinking that you’ve made sense of something is not the same as really having made sense of it. How do we know where we are? Verifiability is one of the keys.
Wolfgang, I don’t mind criticism, really. If you think that I may mistake your post for a criticism, the probably you mistook my thoughts on Qi Qong as a once-and-for-all comment. The heavy mythologised practices I was refering to include the exact number that Chinese tend to follow. For example, instead of a rough number of rounds you should do for a practice, you have to do exactly 81 (say) times; no less and no more. Now as long as no one can show me how to get these numbers; and/or show experimentally the effects of these numbers, I am all against them. Anyone think they have too much time for numbers should spend some time on a rigorous course in number theory instead.
David, I think your definition on energy represents pretty well the common usage in the yogic world. This is all ok for me. But the same group of people also like to say “XXX increases/absorbs my energy”. What do they mean then? Certainly they assume that “energy” is generally a good thing. (In contrast with your relatively natural and open-ended description) Here is a quick example by Wolfgang:
um…I hope the Qi Qong won’t give me “sad energy” or “angry energy”. “negative energy” is another common term from yogis. What’s that? Is “gaining negative energy” a gain or a loss? Finally, can anyone tell me the meaning of “negative loving energy” or “positive sad energy”?
Ok, I’m not trying to point out the correct use of this word. Just to show you guys how confusing this word is. You guys gave me 3 different definitions of “energy”, most of them are quite different from the others.
For David’s definition (not in the sense of being used by David ), I think it’s much clearer if we say that a certain person/teaching/practice will make us happy/filled with (a sense of) love. That is qualitatively clearer than the energy language, and with fewer words. The energy language is mythologised and will only create much misunderstanding.
“the potential for causing changes” is difficult to translate (at least by a Chinese like me) and thus seems to be a good meaning for “energy”. So “increased energy” will then make some more sense.
um…I hope the Qi Qong won’t give me “sad energy” or “angry energy”. “negative energy” is another common term from yogis. What’s that? Is “gaining negative energy” a gain or a loss? Finally, can anyone tell me the meaning of “negative loving energy” or “positive sad energy”?
"gaining negative energy" is a gain. Next we need to come to an understanding of the term "negative" (and positive). Is negative/positive understood with feelings of good and bad ? Or is it understood as an expression of quality like Ying/Yang ? Now I never have heard the term "negative loving energy" and I really don't know what to make of it. May be you should give an example or tell me where you have heard this. And by the way, I also am sceptical about the number crunchers of Qi Gong. All I can say to this is: may be the belief in some magical number helps them to manifest something. In the end, the practitioner does not know if it was the magical number or his own belief that helped him achieve something.
Alvin said:
The energy language is mythologised and will only create much misunderstanding.
That’s true, but at its best, it’s just picturesque and poetic. Unfortunately, at its worst it is misleading as you say.
There are psychological reasons why it is natural and picturesque to say someone is ‘giving off negative energy’, for example. The body-language systems, both expressive and interpretative, in all their richness, evolved to be able to express this ‘energy’. So it is true that, in general, people are giving out constant messages about their internal state, whether they intend it or not.
By the way, Alvin, “negative” as used by people in this domain, tends to ultimately simply mean ‘bad’, or ‘undesirable’.
Hi Dave,
I entirely agree with you.