pair vs span

pair

verb
  • To group into one or more sets of two. 

  • To engage (oneself) with another of opposite opinions not to vote on a particular question or class of questions. 

  • To bring two (animals, notably dogs) together for mating. 

  • To suit; to fit, as a counterpart. 

  • To come together for mating. 

  • to link two electronic devices wirelessly together, especially through a protocol such as Bluetooth 

noun
  • A couple of working animals attached to work together, as by a yoke. 

  • A boat for two sweep rowers. 

  • A score of zero runs (a duck) in both innings of a two-innings match. 

  • Used with binary nouns (often in the plural to indicate multiple instances, since such nouns are plural only, except in some technical contexts) 

  • A double play, two outs recorded in one play. 

  • The exclusion of one member of a parliamentary party from a vote, if a member of the other party is absent for important personal reasons. 

  • Two similar or identical things taken together; often followed by of. 

  • Two members of opposite parties or opinion, as in a parliamentary body, who mutually agree not to vote on a given question, or on issues of a party nature during a specified time. 

  • In a mechanism, two elements, or bodies, which are so applied to each other as to mutually constrain relative motion; named in accordance with the motion it permits, as in turning pair, sliding pair, twisting pair. 

  • One of the constituent items that make up a pair. 

  • A doubleheader, two games played on the same day between the same teams 

  • A poker hand that contains two cards of identical rank, which cannot also count as a better hand. 

  • A pair of breasts 

  • A pair of testicles 

  • Two people in a relationship, partnership or friendship. 

span

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

  • 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 fetter, as a horse; to hobble. 

noun
  • The space of all linear combinations of something. 

  • A portion of something by length; a subsequence. 

  • A small space or a brief portion of time. 

  • 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. 

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