You guys... I leave you alone for one day and immediately you start fighting! Whatever shall I do with you? 
I tend to keep my philosophy about language as simple as possible: the moment enough people start speaking in a certain manner, it becomes a part of that language. Where that treshold is, I don't know exactly, and for the most part, examples stay out of that grey (or gray?) area. However, as much as I dislike it, if everyone started to use it's instead of its and its instead of it's (try wrapping your head around that one), it would suddenly become proper English, much like 'thou', 'doth' or 'sayeth' aren't used anymore (incidentally, aren't used to be amn't, but since people didn't like saying that, they just changed it). Anglosaxons from 1000 years ago wouldn't understand very much, and, in effect, we now have Old English, which is a whole other language.
Language is a mouldable concept. Much like mutations are mistakes that drive evolution, laguages develop and change in accordance with the whims and caprices of the people. Dictionaries attempt to encircle all that is now, but then they are only books written by man, not god. How will you go about indexing and entire language when its boundaries aren't even properly defined? So, dictionaries end up being more like guidebooks (very accurate guidebooks, might I add!) rather than some ultimate dogma that everyone should stick to.
Dictionaries are there to guide you, but just because 'apricity' isn't in many dictionaries doesn't mean it was not used at a point in the past, and just because D'oh! is in there doesn't mean it's appropriate to use in, I don't know, you presidential inauguration speech. In the end, language is the product of its users just as much as the formal rules. I'm not proposing a sort of linguistic anarchism, where everyone could just say whatever and have it be right, as that would lead to utter chaos; however, I also do not propone adhering completely to every little formality, as such constraining of the language would certainly be deleterious. It would appear to me the middle road is best, as with so many other things.
Thus, I conclude that biangbiang is a perfectly valid symbol, even though some dictionaries might lack that entry. Phew!
(If you've made it this far, congrats!)
I tend to keep my philosophy about language as simple as possible: the moment enough people start speaking in a certain manner, it becomes a part of that language. Where that treshold is, I don't know exactly, and for the most part, examples stay out of that grey (or gray?) area. However, as much as I dislike it, if everyone started to use it's instead of its and its instead of it's (try wrapping your head around that one), it would suddenly become proper English, much like 'thou', 'doth' or 'sayeth' aren't used anymore (incidentally, aren't used to be amn't, but since people didn't like saying that, they just changed it). Anglosaxons from 1000 years ago wouldn't understand very much, and, in effect, we now have Old English, which is a whole other language.
Language is a mouldable concept. Much like mutations are mistakes that drive evolution, laguages develop and change in accordance with the whims and caprices of the people. Dictionaries attempt to encircle all that is now, but then they are only books written by man, not god. How will you go about indexing and entire language when its boundaries aren't even properly defined? So, dictionaries end up being more like guidebooks (very accurate guidebooks, might I add!) rather than some ultimate dogma that everyone should stick to.
Dictionaries are there to guide you, but just because 'apricity' isn't in many dictionaries doesn't mean it was not used at a point in the past, and just because D'oh! is in there doesn't mean it's appropriate to use in, I don't know, you presidential inauguration speech. In the end, language is the product of its users just as much as the formal rules. I'm not proposing a sort of linguistic anarchism, where everyone could just say whatever and have it be right, as that would lead to utter chaos; however, I also do not propone adhering completely to every little formality, as such constraining of the language would certainly be deleterious. It would appear to me the middle road is best, as with so many other things.
Thus, I conclude that biangbiang is a perfectly valid symbol, even though some dictionaries might lack that entry. Phew!
(If you've made it this far, congrats!)