cable tray vs sewer

cable tray

noun
  • A rigid structure to support electric cables; a type of raceway, normally having the appearance of a ladder and open at the top to facilitate changes. 

sewer

noun
  • A pipe or system of pipes used to remove human waste and to provide drainage. 

  • One who sews. 

  • A small tortricid moth, the larva of which sews together the edges of a leaf using silk. 

  • A servant attending at a meal who is responsible for seating arrangements, serving dishes, etc. 

verb
  • To provide (a place) with a system of sewers. 

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