A Property Editor is the editor that a Data Type references. A Data Type is defined by a user in the Umbraco backoffice and references a Property Editor. In Umbraco a Property Editor is defined in a JSON manifest file and associated JS files.
When creating a data type, you specify the property editor for the data type to use by selecting from the "property editor" list (as shown below)
Umbraco comes pre-installed with many useful property editors...
- How to create a Property Editor Creating property editors for Umbraco