It is a program able to store huge amounts of disparate data and on request return it back to us. Data is stored in tables. From a technical perspective, the PostgreSQL is a relational database management system - RDBMS. PostgreSQL uses the language SQL (Structured Query Language).
PostgreSQL was developed from the Ingres project at the University of California in 1985 and his original name was Postgres.
PostgreSQL is primarily developed for Linux, but also supports other platforms - UNIX, Windows.
PostgreSQL in practice: PostgreSQL is used mainly by web programmers for a work. Without database nowadays no website or application can work. It is also used for large enterprise applications and solutions. Competitors include MySQL, Oracle, SQL Server and DB2.