celebration vs pep rally

celebration

noun
  • A social gathering for entertainment and fun; a party. 

  • The observance of a holiday or feast day, as by solemnities. 

  • The act, process of showing appreciation, gratitude and/or remembrance, notably as a social event. 

  • The formal performance of a solemn rite, such as Christian sacrament. 

pep rally

noun
  • A meeting or gathering for the purpose of instilling enthusiasm and motivation in attenders. 

  • An extracurricular school activity in which students gather to express support for the school sports team before a game. 

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