principal

adjective | \ ˈprin-sə-pəl \ | prin·ci·pal
  1. : being the main or most important, consequential, or influential their principal place of business the principal obligor

  1. : of, relating to, or constituting principal or a principal the principal amount of the loan

principal

noun
  1. a : one who engages another to act for him or her subject to his or her general control or instruction : one from whom an agent derives authority to act — compare fiduciary

    b : one who commits a crime or instigates, encourages, or assists another to commit it especially when constructively or actually present — see also accessory 1

    — principal in the first degree
    : a principal under common law who intentionally commits and is actually or constructively present at the commission of a crime

    — principal in the second degree
    : a principal under common law who aids, encourages, or commands another to commit a crime and is actually or constructively present when it is committed

    c : the person primarily liable on a legal obligation or one who will ultimately bear the burden because of a duty to indemnify another as distinguished from one (as an endorser, surety, or guarantor) who is secondarily liable

  1. : a capital sum earning interest, due as a debt, or used as a fund shall receive the income from the trust until age 18, and thereafter the principal payments shall be applied first to interest and then to principal; also : the main body of an estate, devise, or bequest : the main body of an estate, devise, or bequest