Abbreviation

People will make abbreviations for whatever the fuck they want, there's no central universal authority on that. ‘Definition’ itself has multiple definitions, incidentally. An abbreviation is a nominal definition, hence it is listed under definitions in a lexicographical book called a dictionary. Because the abbreviation is a definition, it is there with other definitions. 
Because it's a DEFInition, you can ask Google Home to DEFIne ‘crypto,’ or find it in the list of DEFINITIONS at tfd.com https://www.thefreedictionary.com/cryptoG. Eiríksson, 28. Maí, 2020. South Iceland.