The Frappe framework's unit of data modelling โ a definition that generates the table, form, list view, permissions and REST API together.
A DocType is the core modelling primitive of the Frappe framework, which underpins ERPNext. Defining a DocType creates its database table, its form and list views, its permission rules and its REST API at once, and the definition is data rather than code. This is why customisation in ERPNext is often configuration that survives upgrades, instead of modifications that have to be re-applied.
In Frappe, a DocType is both the schema and the interface. Declaring fields on a DocType gives you the table, the form layout, the list view with filters, role permissions and a REST endpoint โ without writing any of them separately.
The practical consequence is the one that matters during an implementation: adding a field, a link between records, or a validation rule is usually a configuration change stored as data. It survives an upgrade, which is not true of forked code in most ERP platforms.