monotonic vs one-note

monotonic

adj
  • Uttered in a monotone; monotonous. 

  • said of a function that either never decreases or never increases as its independent variable increases. 

  • of or using the Greek system of diacritics which discards the breathings and employs a single accent to indicate stress. It replaced polytonic system in 1982. 

one-note

adj
  • Having only one opinion, outlook, tone, etc., especially as expressed repetitively; without variety or range. 

How often have the words monotonic and one-note occurred in a corpus of books? (source: Google Ngram Viewer )