Two way radios come in a variety of different forms but basically is a radio that can both transmit and receive.  Probably the most well known form of a two way radio is the hand-held radio which is more well known as a walkie-talkie or handie-talkie.  There is a huge range of two way radio technologies and types from ones as simple as the walkie-talkie to systems which are far more expensive and complex with multiple channels.  To best understand what a two way radio is, look know further than your cell phone which could be considered in this category because it carries the ability to both transmit and receive.