sprinkler head vs waterer

sprinkler head

noun
  • A heat-activated device that sprays water in the event of a fire, usually mounted on a ceiling. 

waterer

noun
  • A device used for watering. 

  • A device from which livestock, poultry, or pets may drink. 

  • One who waters plants. 

  • One who waters down, or dilutes, something. 

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