Atomicity: either all parts of the transaction complete, or all parts of the transaction don't complete; there's no "partly complete" state

Consistency: the state of the database after a transaction is stable; all "downstream" effects (e.g. triggers) of the query are complete before the transaction is confirmed.

Isolation: concurrent transactions behave the same as sequential transactions

Durability: a power failure or crash won't lose any transactions

Traditionally, ACID is where relational databases shine.