Microsoft Knowledge Base Article 321679 contains the following summary:
This step-by-step article describes how to manage security templates in Windows 2000 server. A security template is a physical representation of a security configuration, and is a file where a group of security settings may be stored. Windows 2000 includes a set of security templates, and each template is based on the role of a computer, from security settings for low security domain clients to highly secure domain controllers. You can use these templates as they are provided, you can modify them, or use them as a basis for creating custom security templates.