ladder vs spectrum

ladder

noun
  • A series of stages by which one progresses to a better position. 

  • A length of unravelled fabric in a knitted garment, especially in nylon stockings; a run. 

  • A frame, usually portable, of wood, metal, or rope, used for ascent and descent, consisting of two side pieces to which are fastened rungs (cross strips or rounds acting as steps). 

  • In the game of go, a sequence of moves following a zigzag pattern and ultimately leading to the capture of the attacked stones. 

  • The hierarchy or ranking system within an organization, such as the corporate ladder. 

verb
  • Of a knitted garment: to develop a ladder as a result of a broken thread. 

  • To ascend (a building, a wall, etc.) using a ladder. 

  • To arrange or form into a shape of a ladder. 

  • To close in on a target with successive salvos, increasing or decreasing the shot range as necessary. 

spectrum

noun
  • A range; a continuous, infinite, one-dimensional set, possibly bounded by extremes. 

  • The pattern of absorption or emission of radiation produced by a substance when subjected to energy (radiation, heat, electricity, etc.). 

  • The image of something seen that persists after the eyes are closed. 

  • Specifically, a range of colours representing light (electromagnetic radiation) of contiguous frequencies; hence electromagnetic spectrum, visible spectrum, ultraviolet spectrum, etc. 

  • The set of eigenvalues of a matrix. 

  • Of a bounded linear operator A, the set of scalar values λ such that the operator A—λI, where I denotes the identity operator, does not have a bounded inverse; intended as a generalisation of the linear algebra sense. 

  • The autism spectrum. 

  • The set, denoted Spec(R), of all prime ideals of a given ring R, commonly augmented with a Zariski topology and considered as a topological space. 

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