Source : Webster's Revised Unabridged Dictionary (1913)

Box \Box\, n.; pl. {Boxes} [As. box a small case or vessel with
   a cover; akin to OHG. buhsa box, G. b["u]chse; fr. L. buxus
   boxwood, anything made of boxwood. See {Pyx}, and cf. {Box} a
   tree, {Bushel}.]
   1. A receptacle or case of any firm material and of various
      shapes.

   2. The quantity that a box contain.

   3. A space with a few seats partitioned off in a theater, or
      other place of public amusement.

            Laughed at by the pit, box, galleries, nay, stage.
                                                  --Dorset.

            The boxes and the pit are sovereign judges.
                                                  --Dryden.

   4. A chest or any receptacle for the deposit of money; as, a
      poor box; a contribution box.

            Yet since his neighbors give, the churl unlocks,
            Damning the poor, his tripple-bolted box. --J.
                                                  Warton.

   5. A small country house. ``A shooting box.'' --Wilson.

            Tight boxes neatly sashed.            --Cowper.

   6. A boxlike shed for shelter; as, a sentry box.

   7. (Mach)
      (a) An axle box, journal box, journal bearing, or bushing.
      (b) A chamber or section of tube in which a valve works;
          the bucket of a lifting pump.

   8. The driver's seat on a carriage or coach.

   9. A present in a box; a present; esp. a Christmas box or
      gift. ``A Christmas box.'' --Dickens.

   10. (Baseball) The square in which the pitcher stands.

   11. (Zo["o]l.) A Mediterranean food fish; the bogue.

   Note: Box is much used adjectively or in composition; as box
         lid, box maker, box circle, etc.; also with modifying
         substantives; as money box, letter box, bandbox, hatbox
         or hat box, snuff box or snuffbox.

   {Box beam} (Arch.), a beam made of metal plates so as to have
      the form of a long box.

   {Box car} (Railroads), a freight car covered with a roof and
      inclosed on the sides to protect its contents.

   {Box chronometer}, a ship's chronometer, mounted in gimbals,
      to preserve its proper position.

   {Box coat}, a thick overcoat for driving; sometimes with a
      heavy cape to carry off the rain.

   {Box coupling}, a metal collar uniting the ends of shafts or
      other parts in machinery.

   {Box crab} (Zo["o]l.), a crab of the genus {Calappa}, which,
      when at rest with the legs retracted, resembles a box.

   {Box drain} (Arch.), a drain constructed with upright sides,
      and with flat top and bottom.

   {Box girder} (Arch.), a box beam.

   {Box groove} (Metal Working), a closed groove between two
      rolls, formed by a collar on one roll fitting between
      collars on another. --R. W. Raymond.

   {Box metal}, an alloy of copper and tin, or of zinc, lead,
      and antimony, for the bearings of journals, etc.

   {Box plait}, a plait that doubles both to the right and the
      left.

   {Box turtle} or

   {Box tortoise} (Zo["o]l.), a land tortoise or turtle of the
      genera {Cistudo} and {Emys}; -- so named because it can
      withdraw entirely within its shell, which can be closed by
      hinged joints in the lower shell. Also, humorously, an
      exceedingly reticent person. --Emerson.

   {In a box}, in a perplexity or an embarrassing position; in
      difficulty. (Colloq.)

   {In the wrong box}, out of one's place; out of one's element;
      awkwardly situated. (Colloq.) --Ridley (1554)

Girder \Gird"er\, n. [From {Gird} to encircle.]
   1. One who, or that which, girds.

   2. (Arch. & Engin.) A main beam; a stright, horizontal beam
      to span an opening or carry weight, such as ends of floor
      beams, etc.; hence, a framed or built-up member
      discharging the same office, technically called a compound
      girder. See Illusts. of {Frame}, and {Doubleframed floor},
      under {Double}.

   {Bowstring girder}, {Box girder}, etc. See under {Bowstring},
      {Box}, etc.

   {Girder bridge}. See under {Bridge}.

   {Lattice girder}, a girder consisting of longitudinal bars
      united by diagonal crossing bars.

   {Half-lattice girder}, a girder consisting of horizontal
      upper and lower bars connected by a series of diagonal
      bars sloping alternately in opposite directions so as to
      divide the space between the bars into a series of
      triangles. --Knight.

   {Sandwich girder}, a girder consisting of two parallel wooden
      beams, between which is an iron plate, the whole clamped
      together by iron bolts.

Source : WordNet®

box girder
     n : a beam built up from boards; has a hollow rectangular cross
         section [syn: {box beam}]