Temporary loan, attachment or detachment of an employee to another company (external) or department (internal), for a specified task and predetermined length of time. While assigned elsewhere, the secondee stays on the payroll of his employer and the employer will charge the receiving company or department a fee. In some countries, temporary agencies may (e.g. the Netherlands) or be legally obliged to (e.g. Germany, Denmark) assign temporary workers as secondees, meaning that the temporary worker will be entitled to receive payment even if no assignment is available. Term mainly used in Western Europe.
Source: Staffing Industry Analysts