The Collaborative International Dictionary of English v.0.48:

Solar \So"lar\, a. [L. solaris, fr. sol the sun; akin to As.
   s[=o]l, Icel. s[=o]l, Goth. sauil, Lith. saule, W. haul,.
   sul, Skr. svar, perhaps to E. sun:F. solaire. Cf. Parasol.
   Sun.]
   1. Of or pertaining to the sun; proceeding from the sun; as,
      the solar system; solar light; solar rays; solar
      influence. See Solar system, below.
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   2. (Astrol.) Born under the predominant influence of the sun.
      [Obs.]
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            And proud beside, as solar people are. --Dryden.
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   3. Measured by the progress or revolution of the sun in the
      ecliptic; as, the solar year.
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   4. Produced by the action of the sun, or peculiarly affected
      by its influence.
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            They denominate some herbs solar, and some lunar.
                                                  --Bacon.
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   Solar cycle. See under Cycle.

   Solar day. See Day, 2.

   Solar engine, an engine in which the energy of solar heat
      is used to produce motion, as in evaporating water for a
      steam engine, or expanding air for an air engine.

   Solar flowers (Bot.), flowers which open and shut daily at
      certain hours.

   Solar lamp, an argand lamp.

   Solar microscope, a microscope consisting essentially,
      first, of a mirror for reflecting a beam of sunlight
      through the tube, which sometimes is fixed in a window
      shutter; secondly, of a condenser, or large lens, for
      converging the beam upon the object; and, thirdly, of a
      small lens, or magnifier, for throwing an enlarged image
      of the object at its focus upon a screen in a dark room or
      in a darkened box.
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   Solar month. See under Month.

   Solar oil, a paraffin oil used an illuminant and lubricant.


   Solar phosphori (Physics), certain substances, as the
      diamond, siulphide of barium (Bolognese or Bologna
      phosphorus), calcium sulphide, etc., which become
      phosphorescent, and shine in the dark, after exposure to
      sunlight or other intense light.

   Solar plexus (Anat.), a nervous plexus situated in the
      dorsal and anterior part of the abdomen, consisting of
      several sympathetic ganglia with connecting and radiating
      nerve fibers; -- so called in allusion to the radiating
      nerve fibers.

   Solar spots. See Sun spots, under Sun.

   Solar system (Astron.), the sun, with the group of
      celestial bodies which, held by its attraction, revolve
      round it. The system comprises the major planets, with
      their satellites; the minor planets, or asteroids, and the
      comets; also, the meteorids, the matter that furnishes the
      zodiacal light, and the rings of Saturn. The satellites
      that revolve about the major planets are twenty-two in
      number, of which the Earth has one (see Moon.), Mars
      two, Jupiter five, Saturn nine, Uranus four, and Neptune
      one. The asteroids, between Mars and Jupiter, thus far
      discovered (1900), number about five hundred, the first
      four of which were found near the beginning of the
      century, and are called Ceres, Pallas, Juno, and Vesta.
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   Note: The principal elements of the major planets, and of the
         comets seen at more than one perihelion passage, are
         exhibited in the following tables:
         [1913 Webster] I. -- Major Planets. Symbol.Name.Mean
         distance -- that of the Earth being unity.Period in
         days.Eccentricity.Inclination of orbit.Diameter in
         miles ?????????????????????
         [1913 Webster] II. -- Periodic Comets. Name.Greatest
         distance from sun.Least distance from sun.Inclination
         of orbit.Perihelion passage. [deg] [min] 54
         Encke's3.314.100.34212 541885.2 ?????????????????????
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   Solar telegraph, telegraph for signaling by flashes of
      reflected sunlight.

   Solar time. See Apparent time, under Time.
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The Collaborative International Dictionary of English v.0.48:

Day \Day\ (d[=a]), n. [OE. day, dai, dei, AS. d[ae]g; akin to
   OS., D., Dan., & Sw. dag, G. tag, Icel. dagr, Goth. dags; cf.
   Skr. dah (for dhagh ?) to burn. [root]69. Cf. Dawn.]
   1. The time of light, or interval between one night and the
      next; the time between sunrise and sunset, or from dawn to
      darkness; hence, the light; sunshine; -- also called
      daytime.
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   2. The period of the earth's revolution on its axis. --
      ordinarily divided into twenty-four hours. It is measured
      by the interval between two successive transits of a
      celestial body over the same meridian, and takes a
      specific name from that of the body. Thus, if this is the
      sun, the day (the interval between two successive transits
      of the sun's center over the same meridian) is called a
      solar day; if it is a star, a sidereal day; if it is
      the moon, a lunar day. See Civil day, Sidereal day,
      below.
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   3. Those hours, or the daily recurring period, allotted by
      usage or law for work.
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   4. A specified time or period; time, considered with
      reference to the existence or prominence of a person or
      thing; age; time.
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            A man who was great among the Hellenes of his day.
                                                  --Jowett
                                                  (Thucyd. )
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            If my debtors do not keep their day, . . .
            I must with patience all the terms attend. --Dryden.
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   5. (Preceded by the) Some day in particular, as some day of
      contest, some anniversary, etc.
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            The field of Agincourt,
            Fought on the day of Crispin Crispianus. --Shak.
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            His name struck fear, his conduct won the day.
                                                  --Roscommon.
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   Note: Day is much used in self-explaining compounds; as,
         daybreak, daylight, workday, etc.
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   Anniversary day. See Anniversary, n.

   Astronomical day, a period equal to the mean solar day, but
      beginning at noon instead of at midnight, its twenty-four
      hours being numbered from 1 to 24; also, the sidereal day,
      as that most used by astronomers.

   Born days. See under Born.

   Canicular days. See Dog day.

   Civil day, the mean solar day, used in the ordinary
      reckoning of time, and among most modern nations beginning
      at mean midnight; its hours are usually numbered in two
      series, each from 1 to 12. This is the period recognized
      by courts as constituting a day. The Babylonians and
      Hindoos began their day at sunrise, the Athenians and Jews
      at sunset, the ancient Egyptians and Romans at midnight.


   Day blindness. (Med.) See Nyctalopia.

   Day by day, or Day after day, daily; every day;
      continually; without intermission of a day. See under
      By. "Day by day we magnify thee." --Book of Common
      Prayer.

   Days in bank (Eng. Law), certain stated days for the return
      of writs and the appearance of parties; -- so called
      because originally peculiar to the Court of Common Bench,
      or Bench (bank) as it was formerly termed. --Burrill.

   Day in court, a day for the appearance of parties in a
      suit.

   Days of devotion (R. C. Ch.), certain festivals on which
      devotion leads the faithful to attend mass. --Shipley.

   Days of grace. See Grace.

   Days of obligation (R. C. Ch.), festival days when it is
      obligatory on the faithful to attend Mass. --Shipley.

   Day owl, (Zool.), an owl that flies by day. See Hawk owl.


   Day rule (Eng. Law), an order of court (now abolished)
      allowing a prisoner, under certain circumstances, to go
      beyond the prison limits for a single day.

   Day school, one which the pupils attend only in daytime, in
      distinction from a boarding school.

   Day sight. (Med.) See Hemeralopia.

   Day's work (Naut.), the account or reckoning of a ship's
      course for twenty-four hours, from noon to noon.

   From day to day, as time passes; in the course of time; as,
      he improves from day to day.

   Jewish day, the time between sunset and sunset.

   Mean solar day (Astron.), the mean or average of all the
      apparent solar days of the year.

   One day, One of these days, at an uncertain time, usually
      of the future, rarely of the past; sooner or later. "Well,
      niece, I hope to see you one day fitted with a husband."
      --Shak.

   Only from day to day, without certainty of continuance;
      temporarily. --Bacon.

   Sidereal day, the interval between two successive transits
      of the first point of Aries over the same meridian. The
      Sidereal day is 23 h. 56 m. 4.09 s. of mean solar time.

   To win the day, to gain the victory, to be successful. --S.
      Butler.

   Week day, any day of the week except Sunday; a working day.


   Working day.
      (a) A day when work may be legally done, in distinction
          from Sundays and legal holidays.
      (b) The number of hours, determined by law or custom,
          during which a workman, hired at a stated price per
          day, must work to be entitled to a day's pay.
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WordNet (r) 3.0 (2006):

solar day
    n 1: time for Earth to make a complete rotation on its axis;
         "two days later they left"; "they put on two performances
         every day"; "there are 30,000 passengers per day" [syn:
         day, twenty-four hours, twenty-four hour period,
         24-hour interval, solar day, mean solar day]