I’ve used Postgres a lot and learned it from my Computer Science 350 class (Applications of Databases). It is a popular choice for many small and large projects and more companies are adopting PostgreSQL now these days. So I just want to give you a brief introduction about what PostgreSQL is.
PostgreSQL is a powerful, open source object-relational database management system which implements the SQL querying language. The original name of PostgreSQL is Postgres therefore, sometimes PostgreSQL is referred as Postgres. Many companies who have built products and solutions used PostgreSQL.
To help understand better what is a relational database management system, it is defined as: a type of database management system (DBMS) that stores data in the form of related tables. It is a key component of many web sites and applications. They provide a structured way to store, organize, and access information.
Source: https://www.postgresql.org/about/