hire purchase vs installment

hire purchase

noun
  • A method of purchasing an item, where the buyer hires it and takes possession of it and pays regular installments. Ownership is only transferred on payment of the final amount. Abbreviated as HP. 

installment

noun
  • The act of installing; installation. 

  • A part of a published or broadcast serial. 

  • One of a series of parts, whether equal or unequal to the other parts of the series, of a given entity or a given process, which part presents or is presented at a particular scheduled interval. 

  • One member of a series of portions of a debt or sum of money, which portions may or may not be equated (depending in part on whether the interest rate is fixed or variable), payment of which portions are serially exacted at regularly scheduled intervals toward satisfaction of the total. Payments of installments are generally mensual, quarterly, triannual, biannual, or annual. 

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