What fo you mean by the term flexible working hours?

Flexible working hours represent an arrangement between the employee and employer that provides the employer with some degree of discretion in terms of the hours that they will work. There are many different arrangements that can be worked out, however, they tend to fall under three basic variations: a) staggered start systems; (b) flex­time systems and flex hours; and (c) variable hour systems.
This kind of work system gives much flexibility to employees to work at will and be productive at same time.