hydro vs spark

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 

spark

noun
  • An electrician. 

  • A small, shining body, or transient light; a sparkle. 

  • Any of various lycaenid butterflies of the Indomalayan genus Sinthusa. 

  • A small amount of something, such as an idea or romantic affection, that has the potential to become something greater, just as a spark can start a fire. 

  • A small particle of glowing matter, either molten or on fire. 

  • A ship's radio operator. 

  • A short or small burst of electrical discharge. 

  • A gallant; a foppish young man. 

  • A beau, lover. 

verb
  • To shoot; to fire 

  • To trigger, kindle into activity (an argument, etc). 

  • To give off a spark or sparks. 

  • To light; to kindle. 

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