commemoration vs reminiscing

commemoration

noun
  • That which serves the purpose of commemorating; a memorial. 

  • The great festival of the Oxford academic year, usually taking place on the third Wednesday after Trinity Sunday. 

  • The act of commemorating; an observance or celebration to honor the memory of some person or event. 

  • The specification of individual saints in the prayers for the dead. 

reminiscing

noun
  • reminiscence 

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