acknowledgment vs affirmation

acknowledgment

noun
  • A recognition as genuine or valid; an avowing or admission in legal form. 

  • The act of a person admitting a child as their own. 

  • A response (ACK) sent by a receiver to indicate successful receipt of a transmission (See Wikipedia article on transmission). 

  • A reward or other expression or token of gratitude. 

  • The act of recognizing in a particular character or relationship; recognition of existence, authority, truth, or genuineness. 

  • A formal statement or document recognizing the fulfillment or execution of a legal requirement or procedure. 

  • An expression of gratitude for a benefit or an obligation. 

  • A message from the addressee informing the originator that the originator's communication has been received and understood. 

  • The act of acknowledging 

affirmation

noun
  • That which is affirmed; a declaration that something is true. 

  • A form of self-forced meditation or repetition; autosuggestion. 

  • The solemn declaration made by Quakers and others incapable of taking an oath. 

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