echelon vs pecking order

echelon

noun
  • A level or rank in an organization, profession, or society. 

  • A formation of troops, ships, etc., in diagonal parallel rows. 

  • A line of riders seeking maximum drafting in a crosswind, resulting in a diagonal line across the road. 

verb
  • To form troops into an echelon. 

adj
  • Of a matrix: having undergone Gaussian elimination with the result that the leading coefficient or pivot (that is, the first nonzero number from the left) of a nonzero row is to the right of the pivot of the row above it, giving rise to a stepped appearance in the matrix. 

pecking order

noun
  • The natural hierarchy of social status and dominance occurring in a group of birds. 

  • The usually informal hierarchy of authority or command, often partial or approximate, as determined by the especially natural propensity for domination of different members of a specific group over each other, such as older brothers and sisters over their younger siblings. 

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