in line vs monotone

in line

adj
  • Suitable or appropriate; keeping with expectations, norms, ideals, or rules. 

  • Positioned in a straight line. 

  • assuming a position in the future. 

adv
  • one behind another; in a queue 

monotone

adj
  • Being, or having the salient properties of, a monotone function. 

  • Having a single unvaried pitch. 

noun
  • A piece of writing in one strain throughout. 

  • A single unvaried tone of speech or a sound. 

verb
  • To speak in a monotone. 

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