The Collaborative International Dictionary of English v.0.48:

H2O \H2O\ n. ([=a]ch`t[=oo]`[=o]"),
   The chemical formula for water.

   Syn: water, hydrogen oxide.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Molecular \Mo*lec"u*lar\, a. [Cf. F. mol['e]culare. See
   Molecule.] (Phys. & Chem.)
   Pertaining to, connected with, produced by, or consisting of,
   molecules; as, molecular forces; molecular groups of atoms,
   etc.
   [1913 Webster]

   Molecular attraction (Phys.), attraction acting between the
      molecules of bodies, and at insensible distances.

   Molecular weight (Chem.), the weight of a molecule of any
      gas or vapor as compared with the hydrogen atom having
      weight of 1 as a standard; the sum of the atomic weights
      of the constituents of a molecule; thus, the molecular
      weight of water (H2O) is 18. For more precise
      measurements, the weight of the carbon isotope carbon-12
      is used as the standard, that isotope having the value of
      12.000. In this systen, now used almost universally, the
      hydrogen atom has a weight of 1.0079.
      [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Type \Type\ (t[imac]p), n. [F. type; cf. It. tipo, from L. typus
   a figure, image, a form, type, character, Gr. ty`pos the mark
   of a blow, impression, form of character, model, from the
   root of ty`ptein to beat, strike; cf. Skr. tup to hurt.]
   1. The mark or impression of something; stamp; impressed
      sign; emblem.
      [1913 Webster]

            The faith they have in tennis, and tall stockings,
            Short blistered breeches, and those types of travel.
                                                  --Shak.
      [1913 Webster]

   2. Form or character impressed; style; semblance.
      [1913 Webster]

            Thy father bears the type of king of Naples. --Shak.
      [1913 Webster]

   3. A figure or representation of something to come; a token;
      a sign; a symbol; -- correlative to antitype.
      [1913 Webster]

            A type is no longer a type when the thing typified
            comes to be actually exhibited.       --South.
      [1913 Webster]

   4. That which possesses or exemplifies characteristic
      qualities; the representative. Specifically:
      (a) (Biol.) A general form or structure common to a number
          of individuals; hence, the ideal representation of a
          species, genus, or other group, combining the
          essential characteristics; an animal or plant
          possessing or exemplifying the essential
          characteristics of a species, genus, or other group.
          Also, a group or division of animals having a certain
          typical or characteristic structure of body maintained
          within the group.
          [1913 Webster]

                Since the time of Cuvier and Baer . . . the
                whole animal kingdom has been universally held
                to be divisible into a small number of main
                divisions or types.               --Haeckel.
          [1913 Webster]
      (b) (Fine Arts) The original object, or class of objects,
          scene, face, or conception, which becomes the subject
          of a copy; esp., the design on the face of a medal or
          a coin.
          [1913 Webster]
      (c) (Chem.) A simple compound, used as a model or pattern
          to which other compounds are conveniently regarded as
          being related, and from which they may be actually or
          theoretically derived.
          [1913 Webster]

   Note: The fundamental types used to express the simplest and
         most essential chemical relations are hydrochloric
         acid, HCl; water, H2O; ammonia, NH3; and methane,
         CH4.
         [1913 Webster]

   5. (Typog.)
      (a) A raised letter, figure, accent, or other character,
          cast in metal or cut in wood, used in printing.
      (b) Such letters or characters, in general, or the whole
          quantity of them used in printing, spoken of
          collectively; any number or mass of such letters or
          characters, however disposed.
          [1913 Webster]

   Note: Type are mostly made by casting type metal in a mold,
         though some of the larger sizes are made from maple,
         mahogany, or boxwood. In the cut, a is the body; b, the
         face, or part from which the impression is taken; c,
         the shoulder, or top of the body; d, the nick
         (sometimes two or more are made), designed to assist
         the compositor in distinguishing the bottom of the face
         from t`e top; e, the groove made in the process of
         finishing, -- each type as cast having attached to the
         bottom of the body a jet, or small piece of metal
         (formed by the surplus metal poured into the mold),
         which, when broken off, leaves a roughness that
         requires to be removed. The fine lines at the top and
         bottom of a letter are technically called ceriphs, and
         when part of the face projects over the body, as in the
         letter f, the projection is called a kern.
         [1913 Webster] The type which compose an ordinary book
         font consist of Roman CAPITALS, small capitals, and
         lower-case letters, and Italic CAPITALS and lower-case
         letters, with accompanying figures, points, and
         reference marks, -- in all about two hundred
         characters. Including the various modern styles of
         fancy type, some three or four hundred varieties of
         face are made. Besides the ordinary Roman and Italic,
         some of the most important of the varieties are
         [1913 Webster] Old English. Black Letter. Old Style.
         French Elzevir. Boldface. Antique. Clarendon. Gothic.
         Typewriter. Script.
         [1913 Webster] The smallest body in common use is
         diamond; then follow in order of size, pearl, agate,
         nonpareil, minion, brevier, bourgeois (or two-line
         diamond), long primer (or two-line pearl), small pica
         (or two-line agate), pica (or two-line nonpareil),
         English (or two-line minion), Columbian (or two-line
         brevier), great primer (or two-line bourgeois), paragon
         (or two-line long primer), double small pica (or
         two-line small pica), double pica (or two-line pica),
         double English (or two-line English), double great
         primer (or two-line great primer), double paragon (or
         two-line paragon), canon (or two-line double pica).
         Above this, the sizes are called five-line pica,
         six-line pica, seven-line pica, and so on, being made
         mostly of wood. The following alphabets show the
         different sizes up to great primer.
         [1913 Webster] Brilliant . . abcdefghijklmnopqrstuvwxyz
         Diamond . . abcdefghijklmnopqrstuvwxyz Pearl . . .
         abcdefghijklmnopqrstuvwxyz Agate . . .
         abcdefghijklmnopqrstuvwxyz Nonpareil . . .
         abcdefghijklmnopqrstuvwxyz Minion . . .
         abcdefghijklmnopqrstuvwxyz Brevier . . .
         abcdefghijklmnopqrstuvwxyz Bourgeois . .
         abcdefghijklmnopqrstuvwxyz Long primer . . .
         abcdefghijklmnopqrstuvwxyz Small pica . .
         abcdefghijklmnopqrstuvwxyz Pica . . . . .
         abcdefghijklmnopqrstuvwxyz English . . .
         abcdefghijklmnopqrstuvwxyz Columbian . . .
         abcdefghijklmnopqrstuvwxyz Great primer . . .
         abcdefghijklmnopqrstuvwxyz
         [1913 Webster] The foregoing account is conformed to
         the designations made use of by American type founders,
         but is substantially correct for England. Agate,
         however, is called ruby, in England, where, also, a
         size intermediate between nonpareil and minion is
         employed, called emerald.
         [1913 Webster]

   Point system of type bodies (Type Founding), a system
      adopted by the type founders of the United States by which
      the various sizes of type have been so modified and
      changed that each size bears an exact proportional
      relation to every other size. The system is a modification
      of a French system, and is based on the pica body. This
      pica body is divided into twelfths, which are termed
      "points," and every type body consist of a given number of
      these points. Many of the type founders indicate the new
      sizes of type by the number of points, and the old names
      are gradually being done away with. By the point system
      type founders cast type of a uniform size and height,
      whereas formerly fonts of pica or other type made by
      different founders would often vary slightly so that they
      could not be used together. There are no type in actual
      use corresponding to the smaller theoretical sizes of the
      point system. In some cases, as in that of ruby, the term
      used designates a different size from that heretofore so
      called.
      [1913 Webster] 1 American 9 Bourgeois [bar] [bar] 11/2
      German [bar] 2 Saxon 10 Long Primer [bar] [bar] 21/2 Norse
      [bar] 3 Brilliant 11 Small Pica [bar] [bar] 31/2 Ruby 12
      Pica [bar] [bar] 4 Excelsior [bar] 41/2 Diamond 14 English
      [bar] [bar] 5 Pearl 16 Columbian [bar] [bar] 51/2 Agate
      [bar] 6 Nonpareil 18 Great Primer [bar] [bar] 7 Minion
      [bar] 8 Brevier 20 Paragon [bar] [bar] Diagram of the
      "points" by which sizes of Type are graduated in the
      "Point System".
      [1913 Webster]

   Type founder, one who casts or manufacture type.

   Type foundry, Type foundery, a place for the manufacture
      of type.

   Type metal, an alloy used in making type, stereotype
      plates, etc., and in backing up electrotype plates. It
      consists essentially of lead and antimony, often with a
      little tin, nickel, or copper.

   Type wheel, a wheel having raised letters or characters on
      its periphery, and used in typewriters, printing
      telegraphs, etc.

   Unity of type (Biol.), that fundamental agreement in
      structure which is seen in organic beings of the same
      class, and is quite independent of their habits of life.
      --Darwin.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Water \Wa"ter\ (w[add]"t[~e]r), n. [AS. w[ae]ter; akin to OS.
   watar, OFries. wetir, weter, LG. & D. water, G. wasser, OHG.
   wazzar, Icel. vatn, Sw. vatten, Dan. vand, Goth. wat[=o], O.
   Slav. & Russ. voda, Gr. 'y`dwr, Skr. udan water, ud to wet,
   and perhaps to L. unda wave. [root]137. Cf. Dropsy,
   Hydra, Otter, Wet, Whisky.]
   1. The fluid which descends from the clouds in rain, and
      which forms rivers, lakes, seas, etc. "We will drink
      water." --Shak. "Powers of fire, air, water, and earth."
      --Milton.
      [1913 Webster]

   Note: Pure water consists of hydrogen and oxygen, H2O, and
         is a colorless, odorless, tasteless, transparent
         liquid, which is very slightly compressible. At its
         maximum density, 39[deg] Fahr. or 4[deg] C., it is the
         standard for specific gravities, one cubic centimeter
         weighing one gram. It freezes at 32[deg] Fahr. or
         0[deg] C. and boils at 212[deg] Fahr. or 100[deg] C.
         (see Ice, Steam). It is the most important natural
         solvent, and is frequently impregnated with foreign
         matter which is mostly removed by distillation; hence,
         rain water is nearly pure. It is an important
         ingredient in the tissue of animals and plants, the
         human body containing about two thirds its weight of
         water.
         [1913 Webster]

   2. A body of water, standing or flowing; a lake, river, or
      other collection of water.
      [1913 Webster]

            Remembering he had passed over a small water a poor
            scholar when first coming to the university, he
            kneeled.                              --Fuller.
      [1913 Webster]

   3. Any liquid secretion, humor, or the like, resembling
      water; esp., the urine.
      [1913 Webster]

   4. (Pharm.) A solution in water of a gaseous or readily
      volatile substance; as, ammonia water. --U. S. Pharm.
      [1913 Webster]

   5. The limpidity and luster of a precious stone, especially a
      diamond; as, a diamond of the first water, that is,
      perfectly pure and transparent. Hence, of the first water,
      that is, of the first excellence.
      [1913 Webster]

   6. A wavy, lustrous pattern or decoration such as is imparted
      to linen, silk, metals, etc. See Water, v. t., 3,
      Damask, v. t., and Damaskeen.
      [1913 Webster]

   7. An addition to the shares representing the capital of a
      stock company so that the aggregate par value of the
      shares is increased while their value for investment is
      diminished, or "diluted." [Brokers' Cant]
      [1913 Webster]

   Note: Water is often used adjectively and in the formation of
         many self-explaining compounds; as, water drainage;
         water gauge, or water-gauge; waterfowl, water-fowl, or
         water fowl; water-beaten; water-borne, water-circled,
         water-girdled, water-rocked, etc.
         [1913 Webster]

   Hard water. See under Hard.

   Inch of water, a unit of measure of quantity of water,
      being the quantity which will flow through an orifice one
      inch square, or a circular orifice one inch in diameter,
      in a vertical surface, under a stated constant head; also
      called miner's inch, and water inch. The shape of the
      orifice and the head vary in different localities. In the
      Western United States, for hydraulic mining, the standard
      aperture is square and the head from 4 to 9 inches above
      its center. In Europe, for experimental hydraulics, the
      orifice is usually round and the head from 1/2 of an inch
      to 1 inch above its top.

   Mineral water, waters which are so impregnated with foreign
      ingredients, such as gaseous, sulphureous, and saline
      substances, as to give them medicinal properties, or a
      particular flavor or temperature.

   Soft water, water not impregnated with lime or mineral
      salts.

   To hold water. See under Hold, v. t.

   To keep one's head above water, to keep afloat; fig., to
      avoid failure or sinking in the struggles of life.
      [Colloq.]

   To make water.
      (a) To pass urine. --Swift.
      (b) (Naut.) To admit water; to leak.

   Water of crystallization (Chem.), the water combined with
      many salts in their crystalline form. This water is
      loosely, but, nevertheless, chemically, combined, for it
      is held in fixed and definite amount for each substance
      containing it. Thus, while pure copper sulphate, CuSO4,
      is a white amorphous substance, blue vitriol, the
      crystallized form, CuSO4.5H2O, contains five molecules
      of water of crystallization.

   Water on the brain (Med.), hydrocephalus.

   Water on the chest (Med.), hydrothorax.
      [1913 Webster]

   Note: Other phrases, in which water occurs as the first
         element, will be found in alphabetical order in the
         Vocabulary.
         [1913 Webster]

WordNet (r) 3.0 (2006):

H2O
    n 1: binary compound that occurs at room temperature as a clear
         colorless odorless tasteless liquid; freezes into ice below
         0 degrees centigrade and boils above 100 degrees
         centigrade; widely used as a solvent [syn: water, H2O]