n Laravel Blade, a "Variable" is a placeholder that represents a changing value in the application. To declare a variable, you use the {{ $variableName }} syntax, assign a value to it in PHP code, and it will render in the Blade template. Variables can be used in control structures like loops and conditionals to create dynamic templates that respond to different inputs. They are essential in Blade templating, extensively used in Laravel applications for creating flexible and reusable templates.