docs/user/setup/docs.user.setup.global

{ "_label": "Global Default" }

Default means automatic. Something that is predefined in the system settings, occurs without change or effort, if you do not choose another option.

For example, If you deal in the currency-Rupee, you can set your default global setting as Rupee. Whenever a transaction takes place in ERPNext, the system will automatically consider Rupee as the default medium of currency, unless you specify otherwise.

Setup > Tools > Global Settings/Defaults

Global Defaults