observance vs onlook

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. 

onlook

noun
  • The act of looking on (something); observation. 

  • One's perspective or outlook. 

  • That which is looked at, regarded, or considered. 

verb
  • To look on or look at; watch; observe; view; regard. 

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