Broadcast Radio is the use of Radio to distribute information one-way to a large population. Examples of broadcast radio include FM Radio, TV, NOAA Radio and more.
Hobby Radio can be either One or Two Way radio communications, for an individual and non-commercial use. Things like Amateur TV, CB Radio, HAM Radio and even RC Toys are all examples of Hobby Radio.
One-Way radio communications consist of a single transmitter, with a single or many receivers allowing many people to receive data at once. Two-way communications consist of two Transmitters and Two Receivers (or Two Transceivers, a combination of a receiver and and a transmitter) operating at the same or alternating times.