1. [n]  a hand tool consisting of two straight arms at right angles; used to construct or test right angles; "the carpenter who built this room must have lost his square"
2. [n]  any artifact having a shape similar to a plane geometric figure with four equal sides and four right angles; "a checkerboard has 64 squares"
3. [n]  an open area at the meeting of two or more streets
4. [n]  (informal) a formal and conservative person with old-fashioned views
5. [n]  someone who doesn't understand what is going on
6. [n]  the product of two equal terms; "nine is the second power of three"; "gravity is inversely proportional to the square of the distance"
7. [n]  (geometry) a plane rectangle with four equal sides and four right angles; a four-sided regular polygon; "you can compute the area of a square if you know the length of its sides"
8. [adv]  firmly and solidly; "hit the ball squarely"; "the bat met the ball squarely"; "planted his great bulk square before his enemy"
9. [adv]  in a square shape; "a squarely cut piece of paper"; "folded the sheet of paper square"
10. [adv]  with honesty and fairness; "dealt squarely with his customers"; "always treated me square"
11. [adv]  in a straight direct way; "looked him squarely in the eye"; "ran square into me"
12. [adj]  (slang) rigidly conventional or old-fashioned
13. [adj]  characterized by honesty and fairness; "a square deal"; "wanted to do the square thing"
14. [adj]  having four equal sides and four right angles or forming a right angle; "a square peg in a round hole"; "a square corner"
15. [v]  make square; "Square the circle"; "square the wood with a file"
16. [v]  raise to the second power
17. [v]  turn the oar, while rowing
18. [v]  turn the paddle; in canoeing
19. [v]  position so as to be square; "He squared his shoulders"
20. [v]  pay someone and settle a debt; "I squared with him"
21. [v]  be compatible with; "one idea squares with another"
22. [v]  cause to match, as of ideas or acts

1. \Square\, n. [OF. esquarre, esquierre, F. ['e]querre a
   carpenter's square (cf. It. squadra), fr. (assumed) LL.
   exquadrare to make square; L. ex + quadrus a square, fr.
   quattuor four. See {Four}, and cf. {Quadrant}, {Squad},
   {Squer} a square.]
   1. (Geom.)
      (a) The corner, or angle, of a figure. [Obs.]
      (b) A parallelogram having four equal sides and four right
          angles.
   2. Hence, anything which is square, or nearly so; as:
      (a) A square piece or fragment.
                He bolted his food down his capacious throat in
                squares of three inches.          --Sir W.
                                                  Scott.
      (b) A pane of glass.
      (c) (Print.) A certain number of lines, forming a portion
          of a column, nearly square; -- used chiefly in
          reckoning the prices of advertisements in newspapers.
      (d) (Carp.) One hundred superficial feet.
   3. An area of four sides, generally with houses on each side;
      sometimes, a solid block of houses; also, an open place or
      area for public use, as at the meeting or intersection of
      two or more streets.
            The statue of Alexander VII. stands in the large
            square of the town.                   --Addison.
   4. (Mech. & Joinery) An instrument having at least one right
      angle and two or more straight edges, used to lay out or
      test square work. It is of several forms, as the T square,
      the carpenter's square, the try-square., etc.
   5. Hence, a pattern or rule. [Obs.]
   6. (Arith. & Alg.) The product of a number or quantity
      multiplied by itself; thus, 64 is the square of 8, for 8
      [times] 8 = 64; the square of a + b is a^{2} + 2ab +
      b^{2}.
   7. Exact proportion; justness of workmanship and conduct;
      regularity; rule. [Obs.]
            They of Galatia [were] much more out of square.
                                                  --Hooker.
            I have not kept my square.            --Shak.
   8. (Mil.) A body of troops formed in a square, esp. one
      formed to resist a charge of cavalry; a squadron. ``The
      brave squares of war.'' --Shak.
   9. Fig.: The relation of harmony, or exact agreement;
      equality; level.
            We live not on the square with such as these.
                                                  --Dryden.
   10. (Astrol.) The position of planets distant ninety degrees
       from each other; a quadrate. [Obs.]
   11. The act of squaring, or quarreling; a quarrel. [R.]
   12. The front of a woman's dress over the bosom, usually
       worked or embroidered. [Obs.] --Shak.
   {Geometrical square}. See {Quadrat}, n., 2.
   {Hollow square} (Mil.), a formation of troops in the shape of
      a square, each side consisting of four or five ranks, and
      the colors, officers, horses, etc., occupying the middle.
   {Least square}, {Magic square}, etc. See under {Least},
      {Magic}, etc.
   {On the square}, or {Upon the square}, in an open, fair
      manner; honestly, or upon honor. [Obs. or Colloq.]
   {On}, or {Upon}, {the square with}, upon equality with; even
      with. --Nares.
   {To be all squares}, to be all settled. [Colloq.] --Dickens.
   {To be at square}, to be in a state of quarreling. [Obs.]
      --Nares.
   {To break no square}, to give no offense; to make no
      difference. [Obs.]
   {To break squares}, to depart from an accustomed order.
   {To see how the squares go}, to see how the game proceeds; --
      a phrase taken from the game of chess, the chessboard
      being formed with squares. [Obs.] --L'Estrange.
   

2. \Square\, a.
   1. (Geom.) Having four equal sides and four right angles; as,
      a square figure.
   2. Forming a right angle; as, a square corner.
   3. Having a shape broad for the height, with rectilineal and
      angular rather than curving outlines; as, a man of a
      square frame.
   4. Exactly suitable or correspondent; true; just.
            She's a most truimphant lady, if report be square to
            her.                                  --Shak.
   5. Rendering equal justice; exact; fair; honest, as square
      dealing.
   6. Even; leaving no balance; as, to make or leave the
      accounts square.
   7. Leaving nothing; hearty; vigorous.
            By Heaven, square eaters. More meat, I say. --Beau.
                                                  & Fl.
   8. (Naut.) At right angles with the mast or the keel, and
      parallel to the horizon; -- said of the yards of a
      square-rigged vessel when they are so braced.
   Note: Square is often used in self-explaining compounds or
         combination, as in square-built, square-cornered,
         square-cut, square-nosed, etc.
   {Square foot}, an area equal to that of a square the sides of
      which are twelwe inches; 144 square inches.
   {Square knot}, a knot in which the terminal and standing
      parts are parallel to each other; a reef knot. See Illust.
      under {Knot}.
   {Square measure}, the measure of a superficies or surface
      which depends on the length and breadth taken conjointly.
      The units of square measure are squares whose sides are
      the linear measures; as, square inches, square feet,
      square meters, etc.
   {Square number}. See {square}, n., 6.
   {Square root of a number} or {quantity} (Math.), that number
      or quantity which, multiplied by itself produces the given
      number or quantity.
   {Square sail} (Naut.), a four-sided sail extended upon a yard
      suspended by the middle; sometimes, the foresail of a
      schooner set upon a yard; also, a cutter's or sloop's sail
      boomed out. See Illust. of {Sail}.
   {Square stern} (Naut.), a stern having a transom and joining
      the counter timbers at an angle, as distinguished from a
      round stern, which has no transom.
   {Three-square}, {Five-square}, etc., having three, five,
      etc., equal sides; as, a three-square file.
   {To get square with}, to get even with; to pay off. [Colloq.]
   

3. \Square\, v. t. [imp. & p. p. {Squared}; p. pr. & vb. n.
   {Squaring}.] [Cf. OF. escarrer, esquarrer. See {Square}, n.]
   1. To form with four sides and four right angles. --Spenser.
   2. To form with right angles and straight lines, or flat
      surfaces; as, to square mason's work.
   3. To compare with, or reduce to, any given measure or
      standard. --Shak.
   4. To adjust; to regulate; to mold; to shape; to fit; as, to
      square our actions by the opinions of others.
            Square my trial To my proportioned strength.
                                                  --Milton.
   5. To make even, so as leave no remainder of difference; to
      balance; as, to square accounts.
   6. (Math.) To multiply by itself; as, to square a number or a
      quantity.
   7. (Astrol.) To hold a quartile position respecting.
            The icy Goat and Crab that square the Scales.
                                                  --Creech.
   8. (Naut.) To place at right angles with the keel; as, to
      square the yards.
   {To square one's shoulders}, to raise the shoulders so as to
      give them a square appearance, -- a movement expressing
      contempt or dislike. --Sir W. Scott.
   {To square the circle} (Math.), to determine the exact
      contents of a circle in square measure. The solution of
      this famous problem is now generally admitted to be
      impossible.
   

4. \Square\, v. i.
   1. To accord or agree exactly; to be consistent with; to
      conform or agree; to suit; to fit.
            No works shall find acceptamce . . . That square not
            truly with the Scripture plan.        --Cowper.
   2. To go to opposite sides; to take an attitude of offense or
      defense, or of defiance; to quarrel. [Obs.]
            Are you such fools To square for this? --Shak.
   3. To take a boxing attitude; -- often with up, sometimes
      with off. [Colloq.] --Dickens.
   

A query language, a precursor to SQL.

["Specifying Queries as Relational Expressions: The SQUARE Data Sublanguage", R.E. Boyce et al, CACM 18(11):621-628 (Nov 1975)].