Node Types are flexible data container that contains groups and fields to define custom entities and structures. Eg. creating entities like news and articles. 

Three different sections can contains Node Types: Regular Node Types, Reusable Node Types and DataSets.

Regular Node Types

Basic kind of node types that contains groups and fields. Field are Single Line, Multi Line, etc. 

Reusable Node Types

Those node types can be reused in regular node types.