backside vs beginning

backside

adj
  • Used other than figuratively or idiomatically: see back, side. 

  • Approaching an obstacle backward 

noun
  • Used other than figuratively or idiomatically: see back, side. 

  • The back side of an estate: the backyard and outbuildings behind a main house, especially (UK dialect, euphemistic) an outhouse. 

  • The reverse or opposite of anything. 

  • A person's buttocks. 

beginning

noun
  • 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 is begun; a rudiment or element. 

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

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

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