level set vs observance

level set

noun
  • A state of mutual understanding among parties 

  • An event consisting of level setting 

  • The set of values x for which a real-valued function f(x) is equal to a given constant. 

verb
  • To establish a baseline of mutual understanding 

observance

noun
  • Observation or the act of watching. 

  • The practice of complying with a law, custom, command or rule. 

  • That which is to be observed. 

  • A rule governing a religious order, especially in the Roman Catholic church. 

  • The custom of celebrating a holiday or similar occasion. 

  • Reverence; homage. 

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