ACID is an acronym that stands for the following terms and is widely used to define the features of a relational database system.  

Atomicity – This attribute ensures that if one part of the transaction fails, the complete transaction fails and the database state remains unaffected.  

Consistency ensures that any transaction moves the database from one legitimate state to another.  

Isolation – This characteristic assures that concurrent transaction execution results in the same system state as if transactions were executed serially.  

Durable means that once a transaction is committed, it will remain so even if power is lost.