span

Etymology 1

From Middle English spanne, from Old English spann, from Proto-Germanic *spannō (“span, handbreadth”). Cognate with Dutch span, spanne, German Spanne. The sense “pair of horses” is probably from Old English ġespan, ġespann (“a joining; a fastening together; clasp; yoke”), from Proto-West Germanic [Term?]. Cognate with Dutch gespan, German Gespann.

noun

1. 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.
2. 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.
3. (by extension) A small space or a brief portion of time.
   He has a short attention span and gets bored within minutes.
   Life's but a span; I'll every inch enjoy. 1699, George Farquhar, The Constant Couple
   The unsilent present is a time of evaporating attention spans, 2007, John Zerzan, Silence
4. A portion of something by length; a subsequence.
   For example, in OpenOffice.org or Microsoft Word, each span of text can have a style that defines key characteristics about the text: • What font it uses • Whether it's normal, bolded, italicized, […] 2004, Robert Harris, Robert Warner, The Definitive Guide to SWT and JFace, page 759
5. (architecture, construction) 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 force of the explosion demolished one pair of piers and two spans of the bridge crashed down into the river on top of the barges. 1961 January, “Talking of Trains: The Severn Bridge disaster”, in Trains Illustrated, page 5
6. (architecture, construction) The length of a cable, wire, rope, chain between two consecutive supports.
7. (nautical) 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.
8. (US, Canada) A pair of horses or other animals driven together; usually, such a pair of horses when similar in color, form, and action.
9. (mathematics) The space of all linear combinations of vectors within a set.
10. (computing) 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.
    We use the term span (also called depth, or dependence depth) to refer to the number of parallel steps assuming an unbounded number of processors. 2017, Ananya Kumar, Guy E. Blelloch, Robert Harper, “Parallel Functional Arrays”, in ACM SIGPLAN Notices, →DOI
11. wingspan of a plane or bird

Etymology 2

From Middle English spannen, from Old English spannan, from Proto-Germanic *spannaną (“to stretch, span”). Cognate with German spannen, Dutch spannen.

verb

1. (transitive) To extend through the distance between or across.
   The suspension bridge spanned the canyon.
   Completed in 1823, Gaunless Bridge was designed by George Stephenson to span the River Gaunless in West Auckland, forming part of a line serving Witton Park Colliery. March 8 2023, “Network News: Grant for repairs at Gaunless Bridge”, in RAIL, number 978, page 9
2. (transitive) To extend through (a time period).
   The parking lot spans three acres.
   The novel spans three centuries.
3. (transitive) To measure by the span of the hand with the fingers extended, or with the fingers encompassing the object.
   to span a space or distance; to span a cylinder
4. (mathematics) To generate an entire space by means of linear combinations.
5. (intransitive, US, dated) To be matched, as horses.
6. (transitive) To fetter, as a horse; to hobble.

Etymology 3

From Middle English span, from Old English spann, from Proto-Germanic *spann, first and third person singular preterit indicative of Proto-Germanic *spinnaną (“to spin”).

verb

1. (dated, now uncommon) simple past of spin
   Five spectators remained in critical condition on Monday, a day after they were injured when a giant pick-up truck span out of control during a stunt show in a Dutch town, killing three people, local officials said. 29 September 2014, Reuters, “Five spectators in critical condition following stunt truck accident”, in Irish Independent, archived from the original on 2016-03-11