span vs spell

span

noun
  • A small space or a brief portion of time. 

  • The space of all linear combinations of something. 

  • A portion of something by length; a subsequence. 

  • The spread or extent of an arch or between its abutments, or of a beam, girder, truss, roof, bridge, or the like, between supports. 

  • The time required to execute a parallel algorithm on an infinite number of processors, i.e. the shortest distance across a directed acyclic graph representing the computation steps. 

  • wingspan of a plane or bird 

  • The length of a cable, wire, rope, chain between two consecutive supports. 

  • Any of various traditional units of length approximating this distance, especially the English handspan of 9 inches forming ⅛ fathom and equivalent to 22.86 cm. 

  • A pair of horses or other animals driven together; usually, such a pair of horses when similar in color, form, and action. 

  • A rope having its ends made fast so that a purchase can be hooked to the bight; also, a rope made fast in the center so that both ends can be used. 

  • The full width of an open hand from the end of the thumb to the end of the little finger used as an informal unit of length. 

verb
  • To extend through the distance between or across. 

  • To extend through (a time period). 

  • To measure by the span of the hand with the fingers extended, or with the fingers encompassing the object. 

  • To generate an entire space by means of linear combinations. 

  • To fetter, as a horse; to hobble. 

spell

noun
  • A period of rest; time off. 

  • An uninterrupted series of alternate overs bowled by a single bowler. 

  • A magical effect or influence induced by an incantation or formula. 

  • An indefinite period of time (usually with a qualifier); by extension, a relatively short distance. 

  • Words or a formula supposed to have magical powers. 

  • A definite period (of work or other activity). 

  • A splinter, usually of wood; a spelk. 

  • The wooden bat in the game of trap ball, or knurr and spell. 

  • A period of illness, or sudden interval of bad spirits, disease etc. 

  • A shift (of work); (rare) a set of workers responsible for a specific turn of labour. 

verb
  • To be able to write or say the letters that form words. 

  • To work in place of (someone). 

  • To constitute; to measure. 

  • To rest (someone or something), to give someone or something a rest or break. 

  • To clarify; to explain in detail. 

  • Of letters: to compose (a word). 

  • To indicate that (some event) will occur. 

  • To rest from work for a time. 

  • To put under the influence of a spell; to affect by a spell; to bewitch; to fascinate; to charm. 

  • To write or say the letters that form a word or part of a word. 

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