diamond drill

Diamond \Di"a*mond\ (?; 277), n. [OE. diamaund, diamaunt, F.
   diamant, corrupted, fr. L. adamas, the hardest iron, steel,
   diamond, Gr. ?. Perh. the corruption is due to the influence
   of Gr. ? transparent. See {Adamant}, {Tame}.]
   1. A precious stone or gem excelling in brilliancy and
      beautiful play of prismatic colors, and remarkable for
      extreme hardness.
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   Note: The diamond is native carbon in isometric crystals,
         often octahedrons with rounded edges. It is usually
         colorless, but some are yellow, green, blue, and even
         black. It is the hardest substance known. The diamond
         as found in nature (called a rough diamond) is cut, for
         use in jewelry, into various forms with many reflecting
         faces, or facets, by which its brilliancy is much
         increased. See {Brilliant}, {Rose}. Diamonds are said
         to be of the first water when very transparent, and of
         the second or third water as the transparency
         decreases.
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   2. A geometrical figure, consisting of four equal straight
      lines, and having two of the interior angles acute and two
      obtuse; a rhombus; a lozenge.
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   3. One of a suit of playing cards, stamped with the figure of
      a diamond.
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   4. (Arch.) A pointed projection, like a four-sided pyramid,
      used for ornament in lines or groups.
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   5. (Baseball) The infield; the square space, 90 feet on a
      side, having the bases at its angles.
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   6. (Print.) The smallest kind of type in English printing,
      except that called brilliant, which is seldom seen.
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   Note: [hand] This line is printed in the type called
         {Diamond}.
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   {Black diamond}, coal; (Min.) See {Carbonado}.

   {Bristol diamond}. See {Bristol stone}, under {Bristol}.

   {Diamond beetle} (Zool.), a large South American weevil
      ({Entimus imperialis}), remarkable for its splendid luster
      and colors, due to minute brilliant scales.

   {Diamond bird} (Zool.), a small Australian bird ({Pardalotus
      punctatus}, family {Ampelid[ae]}.). It is black, with
      white spots.

   {Diamond drill} (Engin.), a rod or tube the end of which is
      set with black diamonds; -- used for perforating hard
      substances, esp. for boring in rock.

   {Diamond finch} (Zool.), a small Australian sparrow, often
      kept in a cage. Its sides are black, with conspicuous
      white spots, and the rump is bright carmine.

   {Diamond groove} (Iron Working), a groove of V-section in a
      roll.

   {Diamond mortar} (Chem.), a small steel mortar used for
      pulverizing hard substances.

   {Diamond-point tool}, a cutting tool whose point is
      diamond-shaped.

   {Diamond snake} (Zool.), a harmless snake of Australia
      ({Morelia spilotes}); the carpet snake.

   {Glazier's diamond}, a small diamond set in a glazier's tool,
      for cutting glass.
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Drill \Drill\, n.
   1. An instrument with an edged or pointed end used for making
      holes in hard substances; strictly, a tool that cuts with
      its end, by revolving, as in drilling metals, or by a
      succession of blows, as in drilling stone; also, a drill
      press.
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   2. (Mil.) The act or exercise of training soldiers in the
      military art, as in the manual of arms, in the execution
      of evolutions, and the like; hence, diligent and strict
      instruction and exercise in the rudiments and methods of
      any business; a kind or method of military exercises; as,
      infantry drill; battalion drill; artillery drill.
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   3. Any exercise, physical or mental, enforced with regularity
      and by constant repetition; as, a severe drill in Latin
      grammar.
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   4. (Zool.) A marine gastropod, of several species, which
      kills oysters and other bivalves by drilling holes through
      the shell. The most destructive kind is {Urosalpinx
      cinerea}.
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   {Bow drill}, {Breast drill}. See under {Bow}, {Breast}.

   {Cotter drill}, or {Traverse drill}, a machine tool for
      drilling slots.

   {Diamond drill}. See under {Diamond}.

   {Drill jig}. See under {Jig}.

   {Drill pin}, the pin in a lock which enters the hollow stem
      of the key.

   {Drill sergeant} (Mil.), a noncommissioned officer whose
      office it is to instruct soldiers as to their duties, and
      to train them to military exercises and evolutions.

   {Vertical drill}, a drill press.
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