What is meant by this is a 220v bulb?

Every electrical device has its operating range of voltage and current for which it is designed for. If it exceed the operating range of voltage, its insulation will damage and device will not work. 220V bulb means the normal working voltage for this bulb is 220V. It can operate on the voltages with a deviation of 5% voltage variation also. this variation depends on the devices and will vary with the manufacturer.