It's not a stupid question. Yes, freezing rain is when rain comes into contact with surfaces and instantly turns into ice.
It is a term usually reserved for when snow falls through a warmer layer of air, then through a sub freezing layer of air. It becomes supercooled (at or below freezing) but doesn't become solid until it hits a surface.
Sometimes people can confuse the term with when rain hits a frozen surface and freezes. Both very dangerous for road travel. The difference with freezing rain is the potential for encasement of things like cars, trees, phone lines etc with a layer of ice.