The Dutch were a formidable world power with a strong military in the 17th century. The English word furlough was borrowed into English from Dutch in 1625. Furlough traces back to the Dutch word verlof, which literally means "permission." The original sense of furlough named a leave of absence granted a governmental or institutional employee, especially a soldier, or the document authorizing such an absence. Over the centuries, furlough also came to name a leave of absence granted an employee by the employer, especially such a leave granted at the employee's request.

These days, folks looking up furlough are probably more interested in the most recent definition: a temporary lack of employment due to economic conditions. It's an interesting coincidence that the tulip mania of the very period from which furlough came to English from Dutch is considered by many to be history's first speculative bubble.