資料來源 : Webster's Revised Unabridged Dictionary (1913)

Month \Month\, n. [OE. month, moneth, AS. m[=o]n?, m[=o]na?;
   akin to m[=o]na moon, and to D. maand month, G. monat, OHG.
   m[=a]n[=o]d, Icel. m[=a]nu?r, m[=a]na?r, Goth. m[=e]n[=o]?s.
   [root]272. See {Moon}.]
   One of the twelve portions into which the year is divided;
   the twelfth part of a year, corresponding nearly to the
   length of a synodic revolution of the moon, -- whence the
   name. In popular use, a period of four weeks is often called
   a month.

   Note: In the common law, a month is a lunar month, or
         twenty-eight days, unless otherwise expressed.
         --Blackstone. In the United States the rule of the
         common law is generally changed, and a month is
         declared to mean a calendar month. --Cooley's
         Blackstone.

   {A month mind}.
   (a) A strong or abnormal desire. [Obs.] --Shak.
   (b) A celebration made in remembrance of a deceased person a
       month after death. --Strype.

   {Calendar months}, the months as adjusted in the common or
      Gregorian calendar; April, June, September, and November,
      containing 30 days, and the rest 31, except February,
      which, in common years, has 28, and in leap years 29.

   {Lunar month}, the period of one revolution of the moon,
      particularly a synodical revolution; but several kinds are
      distinguished, as the {synodical month}, or period from
      one new moon to the next, in mean length 29 d. 12 h. 44 m.
      2.87 s.; the {nodical month}, or time of revolution from
      one node to the same again, in length 27 d. 5 h. 5 m. 36
      s.; the {sidereal}, or time of revolution from a star to
      the same again, equal to 27 d. 7 h. 43 m. 11.5 s.; the
      {anomalistic}, or time of revolution from perigee to
      perigee again, in length 27 d. 13 h. 18 m. 37.4 s.; and
      the {tropical}, or time of passing from any point of the
      ecliptic to the same again, equal to 27 d. 7 h. 43 m. 4.7
      s.

   {Solar month}, the time in which the sun passes through one
      sign of the zodiac, in mean length 30 d. 10 h. 29 m. 4.1
      s.