The term NoSQL generally means Not Only SQL: that is, the underlying database has properties that are different to those of common and traditional database systems. As such, there is no clear distinction that qualifies a database as NoSQL, other than the fact that they do not provide the characteristics of ACID compliance. As such, it would be helpful to understand the nature of ACID properties that have been the mainstay of database systems for many decades, as well as discuss, in brief, the significance of BASE and CAP, two other terminologies central to databases today.