podcast vs relay

podcast

verb
  • To deliver (information) in the form of a programme, especially an audio programme, over the Internet on a regular basis for playback on computers or portable devices such as mobile phones. 

  • To deliver a programme, especially an audio programme, over the Internet on a regular basis for playback on computers or portable devices such as mobile phones. 

noun
  • A programme, especially an audio programme, produced on a regular basis, delivered over the Internet in a compressed digital format and designed for playback on computers or portable devices such as mobile phones. 

  • An individual episode of such a programme. 

relay

verb
  • To pass on or transfer (information). 

noun
  • A track and field discipline where runners take turns in carrying a baton from start to finish. Most common events are 4x100 meter and 4x400 meter competitions. 

  • An electrical actuator that allows a relatively small electrical voltage or current to control a larger voltage or current. 

  • A series of vehicles travelling in sequence. 

  • A new set of horses kept along a specific route so that they can replace animals that are tired. 

  • A new set of hounds. 

  • A new set of anything. 

How often have the words podcast and relay occurred in a corpus of books? (source: Google Ngram Viewer )