level crossing vs zigzag

level crossing

noun
  • An at-grade crossing between a railway line and an ordinary road, with rails and road at the same level. 

zigzag

noun
  • A line or path that proceeds by sharp turns in alternating directions. 

  • One of these sharp turns. 

adj
  • Moving in, or having a zigzag. 

verb
  • To move or to twist in a zigzag manner. 

adv
  • in a zigzag manner or pattern 

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