Nena was an ancient supercontinent that consisted of the cratons of Arctica, Baltica, and East Antarctica. Forming about 1.8 billion years ago, the continent was part of the global supercontinent, Columbia. Nena is an acronym that derives from Northern Europe and North America.

National Emergency Number Association - Professional organization with particular emphasis on 911.

National Emergency Number Association. A professional association of emergency number entities responsible for the planning, implementation, management, and administration of national emergency number issues.

National Emergency Numbering Association. NENA's mission is to foster the technological advancement, availability and implementation of a universal emergency telephone number system.