fest vs festival

fest

noun
  • A gathering for a specified reason or occasion. 

  • An event in which the act denoted by the previous noun occurs. 

festival

noun
  • A feast or feast day. 

  • In mythology, a set of celebrations in the honour of a god. 

  • Fried cornbread. 

  • An event or series of special events centred on the celebration or promotion of some theme or aspect of the community, often held at regular intervals. 

adj
  • Pertaining to a feast or feast day; festive. (Now only as the noun used attributively.) 

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