Glossary
Content type
A content type is a reusable definition of a kind of item or document — its columns, its template and its policies — that can be applied across many lists and libraries so the same thing is described the same way everywhere.
It is the governance tool for organisations with real information management needs: define Contract once, and every library that uses it gets the same metadata and the same retention rules.
For a single internal tool it is usually more machinery than the requirement needs — plain columns on one list are simpler and easier to change. Reach for content types when the same shape has to repeat across departments.