The Collaborative International Dictionary of English v.0.48:

Spar \Spar\, v. t. [OE. sparren, AS. sparrian; akin to G.
   sperren, Icel. sperra; from the noun. [root]171. See Spara
   beam, bar.]
   1. To bolt; to bar. [Obs.] --Chaucer.
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   2. To To supply or equip with spars, as a vessel.
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   Note: A vessel equipped with spars that are too large or too
         small is said to be oversparred or undersparred.
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The Collaborative International Dictionary of English v.0.48:

spar \spar\ (sp[aum]r), n. [AS. spaer in spaerst[=a]n
   chalkstone; akin to MHG. spar, G. sparkalk plaster.] (Min.)
   An old name for a nonmetallic mineral, usually cleavable and
   somewhat lustrous; as, calc spar, or calcite, fluor spar,
   etc. It was especially used in the case of the gangue
   minerals of a metalliferous vein.
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   Blue spar, Cube spar, etc. See under Blue, Cube, etc.
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The Collaborative International Dictionary of English v.0.48:

Spar \Spar\, v. i. [imp. & p. p. Sparred; p. pr. & vb. n.
   Sparring.] [Of uncertain origin; cf. OF. esparer to kick,
   F. ['e]parer, or Icel. sperra to stretch out the legs, to
   struggle.]
   1. To strike with the feet or spurs, as cocks do.
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   2. To use the fists and arms scientifically in attack or
      defense; to contend or combat with the fists, as for
      exercise or amusement; to box.
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            Made believe to spar at Paul with great science.
                                                  --Dickens.
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   3. To contest in words; to wrangle. [Colloq.]
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The Collaborative International Dictionary of English v.0.48:

Spar \Spar\, n. [OE. sparre; akin to D. spar, G. sparren, OHG.
   sparro, Dan. & Sw. sparre, Icel. sparri; of uncertain origin.
   [root]171. Cf. Spar, v. t. ]
   1. (Naut.) A general term any round piece of timber used as a
      mast, yard, boom, or gaff.
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   2. (Arch.) Formerly, a piece of timber, in a general sense;
      -- still applied locally to rafters.
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   3. The bar of a gate or door. [Obs.] --Chaucer.
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   Spar buoy (Naut.), a buoy anchored by one end so that the
      other end rises above the surface of the water.

   Spar deck (Naut.), the upper deck of a vessel; especially,
      in a frigate, the deck which is continued in a straight
      line from the quarter-deck to the forecastle, and on which
      spare spars are usually placed. See under Deck.

   Spar torpedo (Naut.), a torpedo carried on the end of a
      spar usually projecting from the bow of a vessel, and
      intended to explode upon contact with an enemy's ships.
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The Collaborative International Dictionary of English v.0.48:

Spar \Spar\, n.
   1. A contest at sparring or boxing.
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   2. A movement of offense or defense in boxing.
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WordNet (r) 3.0 (2006):

spar
    n 1: any of various nonmetallic minerals (calcite or feldspar)
         that are light in color and transparent or translucent and
         cleavable
    2: a stout rounded pole of wood or metal used to support rigging
    3: making the motions of attack and defense with the fists and
       arms; a part of training for a boxer [syn: spar,
       sparring]
    v 1: furnish with spars
    2: fight with spurs; "the gamecocks were sparring"
    3: box lightly
    4: fight verbally; "They were sparring all night"

The Free On-line Dictionary of Computing (19 January 2023):

SPAR

   Early system on Datatron 200 series.  Listed in CACM 2(5):16
   (May 1959).