radio

1. the transmission and reception of electromagnetic waves of radio frequency, especially those carrying sound messages.

   cellular phones are linked by radio rather than wires

2. the activity or industry of broadcasting sound programmes to the public.

   she has written much material for radio

   a radio station

3. an apparatus for receiving radio programmes.

   he switched the radio on

1. communicate or send a message by radio.

   we radioed for help

early 20th century: from radio- in radio-telegraphy and radio-telegram, based on Latin radius ‘ray, beam’.

1. denoting radio waves or broadcasting.

   radio-controlled

   radiogram

2. connected with rays, radiation, or radioactivity.

   radiogenic

   radiograph

3. belonging to the radius in conjunction with some other part.

   radio-carpal

late 19th century: from radio or radius.