| Site Definition | Site Template |
| A Site Definition is the main structure of a site, including how it looks, what default lists are there, what default features are activated, navigation structure, etc... | Site Template is created from an existing site. When a user customizes a site, template consists of the difference between original site definition and changes made to the site. |
| Site definition files are placed in WFE | Site template is stored in Content Database and can be seen in solution gallery |
| It is the core structure and not dependent on Site Template | Site template is created using one of the site definitions only, so if the site definition is modified or deleted, custom template will not work |
| Customization of site definition is a bit difficult. | Site templates are easy to create and customize. |
| Require admin access on WFE for deploying site definition. | Site owner can deploy the site template. |
| Data/files/content is stored on web server, so performance is better. | Templates are in content database so they are less efficient compared to site definition. |