A more thorough explanation:

A special employer is an employer who has borrowed an employee for a limited period and has temporary responsibility for and control over the employee's work. This means that the special employer is in charge of the employee's work during the time they are borrowed, but the employee still has an employment contract with their original employer.

For example, if a construction company borrows a carpenter from another company to work on a specific project, the construction company becomes the special employer of the carpenter for the duration of the project. The carpenter still has an employment contract with their original employer, but the construction company is responsible for directing and controlling their work during the project.

Another example of a special employer is a temp agency that provides workers to other companies on a temporary basis. The companies that hire the temp workers become the special employers for the duration of the assignment.