In WordPress, a "Block Theme" is a type of theme that supports WordPress' "Full Site Editing" (FSE) features. These features, which came with WordPress version 5.8, allow users to edit not only content but the entire design of their website through blocks.

Block themes, unlike traditional WordPress themes, present all page layouts, header, footer, sidebar and other areas in blocks. This gives users more flexibility and control, as they can now change the entire page structure and design elements directly from within the WordPress editor.

The key features are:

Full Site Editing: Users can change page templates and site-wide elements such as headers and footers directly from the WordPress editor.

Design with Blocks: All page elements are organized as blocks. This gives users a modular and flexible design experience.

Global Styles and Settings: Users can easily apply colors, fonts and other style settings across the entire site.

Advanced Customization: Provides users with extensive customization options, even without coding knowledge.

Block themes play an important role in the future of WordPress, allowing users to manage their websites more easily and flexibly. To use these themes, you need to have an up-to-date version of WordPress.