instability vs proportion

instability

noun
  • The quality of being unstable. 

  • A state that is not in equilibrium, or in which a small change has a large irreversible effect. 

proportion

noun
  • The relation of one part to another or to the whole with respect to magnitude, quantity, or degree. 

  • Harmonious relation of parts to each other or to the whole. 

  • A quantity of something that is part of the whole amount or number. 

  • A statement of equality between two ratios. 

  • Size. 

  • Proper or equal share. 

verb
  • To form symmetrically. 

  • To set or render in proportion. 

  • To divide into proper shares; to apportion. 

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