What's the definition of a word? (was: [css3-text] line break opportunities are based on *syllable* boundaries?)

> In Chinese, Yi, and Hangul, a character represents a syllable as far as I understand, but in Japanese, Kanji characters could have more than one syllable, and also there are cases where multiple characters represent single syllable (like Kana + prolonged sound mark).
>
> Although this part is not normative, it looks like we should replace "syllable" with "grapheme cluster".
>
> Please let me know if this change can be incorrect to any other writing systems listed here than Japanese.

The situation is similar for Chinese as far as I can tell.

Speaking about this, this is editorial but the last time I read the 
spec, I got a little bit perplexed about the definition of "word". Is 
there a plan to briefly mention what a "word" is in the introduction 
section? Or perhaps there should be a glossary that puts "word" and 
"grapheme cluster" together? I doubt that there would be a consistent 
and precise definition throughout the spec but a brief and non-normative 
introduction seems helpful.


Cheers,
Kenny