The default theme in WordPress is the theme that is automatically installed when you first set up a WordPress site.
The default theme is designed to be a simple and basic theme that can be used as a starting point for building a website. It is also used as a fallback theme in case there are issues with the currently active theme.
The default theme is usually included in every WordPress installation and is periodically updated by the WordPress development team to ensure that it remains compatible with the latest version of WordPress. The current default theme for WordPress is Twenty Twenty-Three.