principal vs secondary

principal

noun
  • The first two long feathers of a hawk's wing. 

  • The chief administrator of a school. 

  • A diapason, a type of organ stop on a pipe organ. 

  • The construction that gives shape and strength to a roof, generally a truss of timber or iron; or, loosely, the most important member of a piece of framing. 

  • A dancer at the highest rank within a professional dance company, particularly a ballet company. 

  • The primary participant in a crime. 

  • A security principal. 

  • A legal person that authorizes another (the agent) to act on their behalf; or on whose behalf an agent or gestor in a negotiorum gestio acts. 

  • The chief executive and chief academic officer of a university or college. 

  • The money originally invested or loaned, on which basis interest and returns are calculated. 

  • A partner or owner of a business. 

  • One of the turrets or pinnacles of waxwork and tapers with which the posts and centre of a funeral hearse were formerly crowned 

adj
  • Chosen or assumed among a branch of possible values of a multi-valued function so that the function is single-valued. 

  • Primary; most important; first level in importance. 

secondary

noun
  • Any flight feather attached to the ulna (forearm) of a bird. 

  • One who occupies a subordinate or auxiliary place; a delegate deputy. 

  • A radar return generated by the response of an aircraft's transponder to an interrogation signal broadcast by a radar installation, containing additional encoded identification and situational data not available from a simple primary return. 

  • The defensive backs. 

  • An inductive coil or loop that is magnetically powered by a primary in a transformer or similar. 

  • A satellite. 

  • An act of issuing more stock by an already publicly traded corporation. 

  • The second stage of a multistage thermonuclear weapon, which generates a fusion explosion when imploded as an indirect result of the fission explosion of the primary, and which, in a few extremely large weapons, itself implodes a fusion tertiary. 

  • A secondary circle. 

  • A secondary school. 

  • Anything secondary or of lesser importance. 

adj
  • Produced by alteration or deposition subsequent to the formation of the original rock mass. 

  • Derived from a parent compound by replacement of two atoms of hydrogen by organic radicals 

  • Developed by pressure or other causes. 

  • Dependent or consequent upon another disease, or occurring in the second stage of a disease. 

  • Related to secondary education, i.e. schooling between the ages of (approximately) 11 and 18. 

  • Of less than primary importance. 

  • Originating from a deputy or delegated person or body 

  • Representing a reversion to an ancestral state. 

  • Formed by mixing primary colors. 

  • Next in order to the first or primary; of second place in origin, rank, etc. 

  • Pertaining to the second joint of the wing of a bird. 

  • Relating to the manufacture of goods from raw materials. 

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