There is no standard definition of what NoSQL means. The term began with a workshop organized in 2009, but there is much argument about what databases can truly be called NoSQL. But while there is no formal definition, there are some common characteristics of NoSQL databases: * they don’t use the relational data model, and thus don’t use the SQL language * they tend to be designed to run on a cluster * they tend to be Open Source * they don’t have a fixed schema, allowing you to store any data in any record

Presentation, Marti Fowler and Pramod Sadalage, 2012 [Fowler Article]