Answer:
ALL the radio waves that flow out of the source carry ALL of the radio energy that the source generates.
You're the person who wants to catch those waves and get ahold of the information they carry ... whether it's the color of the light, the picture of the game, or the weather forecast. Your task is to figure out how to intercept ENOUGH of that energy to do what you need to do in order to strip that information out of it.
The farther you are from the source, the thinner all that energy is spread out, so the bigger collector you need.
Your energy collector at the receiving end is what's called your "antenna".