decline vs gradient

decline

noun
  • A sloping downward, e.g. of a hill or road. 

  • A weakening. 

  • Downward movement, fall. 

  • A reduction or diminution of activity. 

  • The act of declining or refusing something. 

verb
  • To choose not to do something; refuse, forbear, refrain. 

  • To run through from first to last; to recite in order as though declining a noun. 

  • To cause to decrease or diminish. 

  • To bend downward; to bring down; to depress; to cause to bend, or fall. 

  • To turn or bend aside; to deviate; to stray; to withdraw. 

  • To move downwards, to fall, to drop. 

  • To inflect for case, number, gender, and the like. 

  • To reject a penalty against the opposing team, usually because the result of accepting it would benefit the non-penalized team less than the preceding play. 

  • To become weaker or worse. 

  • To recite all the different declined forms of (a word). 

gradient

noun
  • A slope or incline. 

  • The ratio of the rates of change of a dependent variable and an independent variable, the slope of a curve's tangent. 

  • A differential operator that maps each point of a scalar field to a vector pointed in the direction of the greatest rate of change of the scalar. Notation for a scalar field φ: ∇φ 

  • A gradual change in color. A color gradient; gradation. 

  • The rate at which a physical quantity increases or decreases relative to change in a given variable, especially distance. 

  • A rate of inclination or declination of a slope. 

adj
  • Adapted for walking, as the feet of certain birds. 

  • Moving by steps; walking. 

  • Rising or descending by regular degrees of inclination. 

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