application vs purchase order

application

noun
  • A petition, entreaty, or other request, with the adposition for denoting the subject matter. 

  • The act of directing or referring something to a particular case, to discover or illustrate agreement or disagreement, fitness, or correspondence. 

  • The act of applying as a means; the employment of means to accomplish an end; specific use. 

  • The act of applying or laying on, in a literal sense 

  • A kind of needlework; appliqué. 

  • The substance applied. 

  • The act of requesting, claiming, or petitioning something. 

  • A computer program or the set of software that the end user perceives as a single entity as a tool for a well-defined purpose. (Also called: application program; application software.) 

  • Diligence; close thought or attention. 

  • A verbal or written request for assistance or employment or admission to a school, course or similar. 

purchase order

noun
  • A commercial document issued by a buyer to a seller, indicating the type, quantities and agreed prices for products or services the seller will provide to the buyer. 

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