prime vs principal

prime

adj
  • First in importance, degree, or rank. 

  • First in time, order, or sequence. 

  • Having its complement closed under multiplication: said only of ideals. 

  • First in excellence, quality, or value. 

  • Early; blooming; being in the first stage. 

  • Such that if it divides a product, it divides one of the multiplicands. 

  • Having exactly two integral factors: itself and unity (1 in the case of integers). 

  • Marked or distinguished by the prime symbol. 

verb
  • To apply priming to (a musket or cannon); to apply a primer to (a metallic cartridge). 

  • To mark with a prime mark. 

  • To apply a coat of primer paint to. 

  • To prepare a mechanism for its main work. 

  • To serve as priming for the charge of a gun. 

  • To work so that foaming occurs from too violent ebullition, which causes water to become mixed with, and be carried along with, the steam that is formed. 

  • To prepare; to make ready; to instruct beforehand; to coach. 

noun
  • An inch, as composed of twelve seconds in the duodecimal system. 

  • Six consecutive blocks, which prevent the opponent's pieces from passing. 

  • A four-card hand containing one card of each suit in the game of primero; the opposite of a flush in poker. 

  • The symbol ′ used to indicate feet, minutes, derivation and other measures and mathematical operations. 

  • The religious service appointed to this hour. 

  • The most active, thriving, or successful stage or period. 

  • A prime element of a mathematical structure, particularly a prime number. 

  • A feather, from the wing of the cock ostrich, that is of the palest possible shade. 

  • The first defensive position, with the sword hand held at head height, and the tip of the sword at head height. 

  • The first hour of daylight; the first canonical hour. 

  • The chief or best individual or part. 

  • The first note or tone of a musical scale. 

  • An intermediate sprint within a race, usually offering a prize and/or points. 

principal

adj
  • Primary; most important; first level in importance. 

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

noun
  • 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. 

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

  • 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 

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