equation vs prescription

equation

noun
  • The act or process of equating two or more things, or the state of those things being equal (that is, identical). 

  • An assertion that two expressions are equal, expressed by writing the two expressions separated by an equal sign; from which one is to determine a particular quantity. 

  • A small correction to observed values to remove the effects of systematic errors in an observation. 

prescription

noun
  • Synonym of enactment, the act of establishing a law, regulation, etc., particularly in writing; an instance of this. 

  • A written order from an authorized medical practitioner for provision of a medicine or other treatment, such as (ophthalmology) the specific lenses needed for a pair of glasses. 

  • An established time period after which a person who has uninterruptedly, peacefully, and publicly used another's property acquires full ownership of it. 

  • An established time period within which a right must be exercised and after which it is null and permanently unenforceable. 

  • The act of establishing or formalizing ideal norms for language use, as opposed to describing the actual norms of such use; an instance of this. 

  • Any plan of treatment or planned treatment. 

  • The medicine or treatment provided by such an order. 

adj
  • only available with a physician or nurse practitioner's written prescription 

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