They function basically the same. The primary difference is that a radio controlled toy is completely wireless, which allows for a greater range of motion for the toy. Remote control toys have a wire that connects the transmitter to the toy. This makes it necessary for the operator to follow the toy and stay close by.
A cursory search on the internet will reveal that the two terms are used nearly interchangeably, especially in advertising. The great majority of toys advertised are radio control toys, (even though they may call themselves remote control toys) those that have wireless transmitters. You will also find that most websites abbreviate the term radio control toys to RC toys.
A personal note to remote control toys is that they are usually of inferior quality and do not last long. It is also easy for the wire of remote control toys to become entangled in the toy, especially for young children. But a plus is that you will always know where your transmitter is. If you have young children, the transmitter can easily become misplaced on radio control toys.
For clarity purposes, this article will only discuss radio control toys.