initial vs subscribe

initial

verb
  • To sign one's initial(s), as an abbreviated signature. 

adj
  • Spatially first, placed at the beginning, in the first position; especially said of the first letter of a word. 

  • Chronologically first, early; of or pertaining to the beginning, cause or origin. 

noun
  • A distinguished initial letter of a chapter or section of a document. 

  • onset, part of a syllable that precedes the syllable nucleus in phonetics and phonology. 

  • The first letter of a word or a name. 

  • In plural, the first letter of each word of a person's full name considered as a unit. 

subscribe

verb
  • To sign; to mark with one's signature as a token of consent or attestation. 

  • To sign up to have copies of a publication, such as a newspaper or a magazine, delivered for a period of time. 

  • To agree to buy shares in a company. 

  • To pay money to be a member of an organization. 

  • To contribute or promise to contribute money to a common fund. 

  • To indicate interest in the communications made by a person or organization. 

  • To believe or agree with a theory or an idea (used with to). 

  • To pay for the provision of a service, such as Internet access or a cell phone plan. 

  • To register for notifications about an event or similar. 

  • To promise to give, by writing one's name with the amount. 

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