The Collaborative International Dictionary of English v.0.48:

Thermometer \Ther*mom"e*ter\ (th[~e]r*m[o^]m"[-e]*t[~e]r), n.
   [Thermo- + -meter: cf. F. thermom[`e]tre. See Thermal.]
   (Physics)
   An instrument for measuring temperature, founded on the
   principle that changes of temperature in bodies are
   accompanied by proportional changes in their volumes or
   dimensions.
   [1913 Webster]

   Note: The thermometer usually consists of a glass tube of
         capillary bore, terminating in a bulb, and containing
         mercury or alcohol, which expanding or contracting
         according to the temperature to which it is exposed,
         indicates the degree of heat or cold by the amount of
         space occupied, as shown by the position of the top of
         the liquid column on a graduated scale. See
         Centigrade, Fahrenheit, and R['e]aumur.
         [1913 Webster] To reduce degrees Fahrenheit to degrees
         Centigrade, subtract 32[deg] and multiply by 5/9; to
         reduce degrees Centigrade to degrees Fahrenheit,
         multiply by 9/5 and add 32[deg].
         [1913 Webster]

   Air thermometer, Balance thermometer, etc. See under
      Air, Balance, etc.

   Metallic thermometer, a form of thermometer indicating
      changes of temperature by the expansion or contraction of
      rods or strips of metal.

   Register thermometer, or Self-registering thermometer, a
      thermometer that registers the maximum and minimum of
      temperature occurring in the interval of time between two
      consecutive settings of the instrument. A common form
      contains a bit of steel wire to be pushed before the
      column and left at the point of maximum temperature, or a
      slide of enamel, which is drawn back by the liquid, and
      left within it at the point of minimum temperature.
      [1913 Webster] Thermometric

The Collaborative International Dictionary of English v.0.48:

Air \Air\ ([^a]r), n. [OE. air, eir, F. air, L. a["e]r, fr. Gr.
   'ah`r, air, mist, for 'a[digamma]hr, fr. root 'a[digamma] to
   blow, breathe, probably akin to E. wind. In sense 10 the
   French has taking a meaning fr. It. aria atmosphere, air, fr.
   the same Latin word; and in senses 11, 12, 13 the French
   meaning is either fr. L. aria, or due to confusion with F.
   aire, in an older sense of origin, descent. Cf. A["e]ry,
   Debonair, Malaria, Wind.]
   1. The fluid which we breathe, and which surrounds the earth;
      the atmosphere. It is invisible, inodorous, insipid,
      transparent, compressible, elastic, and ponderable.
      [1913 Webster]

   Note: By the ancient philosophers, air was regarded as an
         element; but modern science has shown that it is
         essentially a mixture of oxygen and nitrogen, with a
         small amount of carbon dioxide, the average proportions
         being, by volume: oxygen, 20.96 per cent.; nitrogen,
         79.00 per cent.; carbon dioxide, 0.04 per cent. These
         proportions are subject to a very slight variability.
         Air also always contains some vapor of water.
         [1913 Webster]

   2. Symbolically: Something unsubstantial, light, or volatile.
      "Charm ache with air." --Shak.
      [1913 Webster]

            He was still all air and fire. [Air and fire being
      the finer and quicker elements as opposed to earth and
      water.]                                     --Macaulay
      .
      [1913 Webster]

   3. A particular state of the atmosphere, as respects heat,
      cold, moisture, etc., or as affecting the sensations; as,
      a smoky air, a damp air, the morning air, etc.
      [1913 Webster]

   4. Any a["e]riform body; a gas; as, oxygen was formerly
      called vital air. [Obs.]
      [1913 Webster]

   5. Air in motion; a light breeze; a gentle wind.
      [1913 Webster]

            Let vernal airs through trembling osiers play.
                                                  --Pope.
      [1913 Webster]

   6. Odoriferous or contaminated air.
      [1913 Webster]

   7. That which surrounds and influences.
      [1913 Webster]

            The keen, the wholesome air of poverty.
                                                  --Wordsworth.
      [1913 Webster]

   8. Utterance abroad; publicity; vent.
      [1913 Webster]

            You gave it air before me.            --Dryden.
      [1913 Webster]

   9. Intelligence; information. [Obs.] --Bacon.
      [1913 Webster]

   10. (Mus.)
       (a) A musical idea, or motive, rhythmically developed in
           consecutive single tones, so as to form a symmetrical
           and balanced whole, which may be sung by a single
           voice to the stanzas of a hymn or song, or even to
           plain prose, or played upon an instrument; a melody;
           a tune; an aria.
       (b) In harmonized chorals, psalmody, part songs, etc.,
           the part which bears the tune or melody -- in modern
           harmony usually the upper part -- is sometimes called
           the air.
           [1913 Webster]

   11. The peculiar look, appearance, and bearing of a person;
       mien; demeanor; as, the air of a youth; a heavy air; a
       lofty air. "His very air." --Shak.
       [1913 Webster]

   12. Peculiar appearance; apparent character; semblance;
       manner; style.
       [1913 Webster]

             It was communicated with the air of a secret.
                                                  --Pope.
       [1913 Webster]

   12. pl. An artificial or affected manner; show of pride or
       vanity; haughtiness; as, it is said of a person, he puts
       on airs. --Thackeray.
       [1913 Webster]

   14. (Paint.)
       (a) The representation or reproduction of the effect of
           the atmospheric medium through which every object in
           nature is viewed. --New Am. Cyc.
       (b) Carriage; attitude; action; movement; as, the head of
           that portrait has a good air. --Fairholt.
           [1913 Webster]

   15. (Man.) The artificial motion or carriage of a horse.
       [1913 Webster]

   Note: Air is much used adjectively or as the first part of a
         compound term. In most cases it might be written
         indifferently, as a separate limiting word, or as the
         first element of the compound term, with or without the
         hyphen; as, air bladder, air-bladder, or airbladder;
         air cell, air-cell, or aircell; air-pump, or airpump.
         [1913 Webster]

   Air balloon. See Balloon.

   Air bath.
       (a) An apparatus for the application of air to the body.
       (b) An arrangement for drying substances in air of any
           desired temperature.

   Air castle. See Castle in the air, under Castle.

   Air compressor, a machine for compressing air to be used as
      a motive power.

   Air crossing, a passage for air in a mine.

   Air cushion, an air-tight cushion which can be inflated;
      also, a device for arresting motion without shock by
      confined air.

   Air fountain, a contrivance for producing a jet of water by
      the force of compressed air.

   Air furnace, a furnace which depends on a natural draft and
      not on blast.

   Air line, a straight line; a bee line. Hence

   Air-line, adj.; as, air-line road.

   Air lock (Hydr. Engin.), an intermediate chamber between
      the outer air and the compressed-air chamber of a
      pneumatic caisson. --Knight.

   Air port (Nav.), a scuttle or porthole in a ship to admit
      air.

   Air spring, a spring in which the elasticity of air is
      utilized.

   Air thermometer, a form of thermometer in which the
      contraction and expansion of air is made to measure
      changes of temperature.

   Air threads, gossamer.

   Air trap, a contrivance for shutting off foul air or gas
      from drains, sewers, etc.; a stench trap.

   Air trunk, a pipe or shaft for conducting foul or heated
      air from a room.

   Air valve, a valve to regulate the admission or egress of
      air; esp. a valve which opens inwardly in a steam boiler
      and allows air to enter.

   Air way, a passage for a current of air; as the air way of
      an air pump; an air way in a mine.

   In the air.
       (a) Prevalent without traceable origin or authority, as
           rumors.
       (b) Not in a fixed or stable position; unsettled.
       (c) (Mil.) Unsupported and liable to be turned or taken
           in flank; as, the army had its wing in the air.

   on the air, currently transmitting; live; -- used of radio
      and television broadcasts, to indicate that the images and
      sounds being picked up by cameras and microphones are
      being broadcast at the present moment.

   Note: In call-in programs where individuals outside a radio
         or television studio have telephoned into the station,
         when their voice is being directly broadcast, the host
         of the program commonly states "You're on the air." as
         a warning that the conversation is not private.

   To take air, to be divulged; to be made public.

   To take the air, to go abroad; to walk or ride out.
      [1913 Webster]

WordNet (r) 3.0 (2006):

air thermometer
    n 1: thermometer that measures temperature by changes in the
         pressure of a gas kept at constant volume [syn: gas
         thermometer, air thermometer]