principal vs relief

principal

noun
  • A partner or owner of a business. 

  • 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. 

  • 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. 

relief

noun
  • The person who takes over a shift for another. 

  • The feeling associated with the removal of stress or discomfort. 

  • Release from a post or duty, as when replaced by another. 

  • A type of sculpture or other artwork in which shapes or figures protrude from a flat background. 

  • A certain fine or composition paid by the heir of a tenant upon the death of the ancestor. 

  • A lowering of a tax through special provisions; tax relief. 

  • The apparent difference in elevation in the surface of a painting or drawing made noticeable by a variation in light or color. 

  • Aid or assistance offered in time of need. 

  • The removal of stress or discomfort. 

  • The supposed projection of a charge from the surface of a field, indicated by shading on the sinister and lower sides. 

  • Court-ordered compensation, aid, or protection, a redress. 

  • The difference of elevations on a surface. 

adj
  • Characterized by surface inequalities. 

  • Of or used in letterpress. 

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