Usually, technical standards are created by dedicated standards bodies such as ISO, DIN or ANSI. But I heard that there is supposed to be another construct which can be produced by professional organizations which are not strandards bodies, and that there is legislation in the EU that this construct is treated almost like a standard. I believe that W3C recommendations or RDA recommendations are an example for that.
Is it correct that such a construct exists? If yes, what is its proper name in European legislation? Also, what are the main similarities and differences between that construct and true standards from a legal point of view?