In German-speaking countries, the usual term for a sparkling wine produced according to certain quality criteria; among other things, it must be produced from quality wine with a second fermentation. The individual regulations (e.g. alcohol content, maturation time on the yeast, etc.) are partly different in Germany and Austria. This may also be called sparkling wine. See the individual steps under Champagne.
Serious sources on the internet are rare - and Wine lexicon from wein.plus is one such source. When researching for my articles, I regularly consult the wein.plus encyclopaedia. There I get reliable and detailed information.Thomas Götz
Weinberater, Weinblogger und Journalist; Schwendi