Wiktionary
abbr. (context Internet slang text messaging English) next.
Wikipedia
Nxt is an open source cryptocurrency and payment network launched in November 2013 by anonymous software developer BCNext. It uses proof-of-stake to reach consensus for transactions - as such there is a static money supply and, unlike bitcoin, no mining. Nxt was specifically conceived as a flexible platform around which to build applications and financial services. It has an integrated Asset Exchange (comparable to shares), messaging system and marketplace. Users can also create new currencies within the system. The last major release enabled Multisignature capabilities and a plugin-system for the client.
Nxt has been covered extensively in the "Call for Evidence" report by ESMA, to which the Nxt community responded in July 2015.