beginning vs proemium

beginning

noun
  • That which is begun; a rudiment or element. 

  • The act of doing that which begins anything; commencement of an action, state, or space of time; entrance into being or upon a course; the first act, effort, or state of a succession of acts or states. 

  • The initial portion of some extended thing. 

  • That which begins or originates something; the source or first cause. 

adj
  • Of or relating to the first portion of some extended thing. 

proemium

noun
  • A preface or introduction; a proem. 

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