Radio

**Definition:** The transmission and reception of electric impulses or signals by means of electric waves without a connecting wire, or the use of these waves for the wireless transmission of electric impulses into which sound is converted. (From Webster's 3d)

**Tree numbers:** - J01.897.280.500.739 - L01.462.500.590.700 - L01.462.500.820.090.739 - L01.462.500.847.514