Candlestick switch - It has at least functional keys to light points of light, it can control separate circuits, eg. In the living room we have 4 lighting fixtures, with one button we can turn on two of them and the other with the other.
Double switch - otherwise known as a two-pole switch, it has one button that turns on the lighting, you can connect several lighting points to it, but we can no longer control them as in the case of a candlestick.