pledge vs security

pledge

noun
  • A bailment of personal property to secure payment of a debt without transfer of title. 

  • A solemn promise to do something. 

  • The personal property so pledged, to be kept until the debt is paid. 

  • A person who has taken a pledge of allegiance to a college fraternity, but is not yet formally approved. 

  • A drinking toast. 

  • An asset or person temporarily handed over to guarantee the fulfilment of something promised, under threat of permanent loss of the thing handed over; surety, security, hostage. 

  • A promise to abstain from drinking alcohol. 

verb
  • To deposit something as a security; to pawn. 

  • To make a solemn promise (to do something). 

  • To give assurance of friendship by the act of drinking; to drink to one's health. 

security

noun
  • Property etc. temporarily relinquished to guarantee repayment of a loan. 

  • Proof of ownership of stocks, bonds or other investment instruments. 

  • Something that secures the fulfillment of an obligation or law. 

  • A guarantee. 

  • The condition of not being threatened, especially physically, psychologically, emotionally, or financially. 

  • Something that secures. 

  • An organization or department responsible for providing security by enforcing laws, rules, and regulations as well as maintaining order. 

  • Freedom from apprehension. 

  • A tradeable financial asset, such as a share of stock.ᵂ 

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