In a family floater, one pool of cover (say ₹5 lakh) can be used by any covered member, in any combination, during the year. It's efficient because not everyone falls ill at once - but a single large claim can consume most of the pool, leaving little for others. The alternative is an individual sum insured per member (more cover, higher premium).
In India
The default structure in Indian corporate GMC. The debate at renewal is almost always “floater vs individual” and “how many dependants” (spouse, 2 kids, and - often - parents/in-laws).
In practice
A ₹5 lakh floater covers employee + spouse + 2 children. The spouse's maternity and the employee's minor surgery in the same year together use ₹4.6 lakh - fine, because it's one shared pool rather than four small separate limits.