hydro vs wall wart

hydro

noun
  • electrical power supply; specifically, electrical power provided by a utility (as a publicly-owned one); payment or bills for this. 

  • hydroelectric power 

adj
  • hydroelectric 

  • hydroponic 

wall wart

noun
  • a power supply which plugs directly to the mains socket, without an intervening cord, and via a cord connects to power the device it is used for 

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