PostgreSQL is an open-source database system: software that stores and organizes information so an app can save it, find it, or update it later. People often shorten its name to “Postgres.”
Think of it as a carefully organized set of tables. A shop app might keep customer details, products, and orders in related tables.
PostgreSQL is one database choice among many. A team chooses based on the product's needs and how it plans to operate and maintain the system.