adherence vs fluctuation

adherence

noun
  • An extent to which a patient continues an agreed treatment plan. 

  • The fulfilment of the legal obligation of residing with wife or husband. 

  • Faithful support for some cause. 

  • A close physical union of two objects. 

fluctuation

noun
  • A wavering; unsteadiness. 

  • In medicine, a wave-like motion or undulation of a fluid in a natural or abnormal cavity (e.g. pus in an abscess), which is felt during palpation or percussion. 

  • A motion like that of waves; a moving in this and that direction. 

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