first vs initial

first

noun
  • A first-edition copy of some publication. 

  • first base 

  • A fraction whose (integer) denominator ends in the digit 1. 

  • The first gear of an engine. 

  • Something that has never happened before; a new occurrence. 

  • A first-class honours degree. 

  • The person or thing in the first position. 

adv
  • For the first time. 

  • Before anything else; firstly. 

  • Now. 

adj
  • Preceding all others of a series or kind; the ordinal of one; earliest. 

  • Of or belonging to a first family. 

  • Most eminent or exalted; most excellent; chief; highest. 

initial

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. 

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. 

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

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