month

n. [ OE. month, moneth, AS. mōnð, mōnað; akin to mōna moon, and to D. maand month, G. monat, OHG. mānōd, Icel. mānuðr, mānaðr, Goth. mēnōþs. √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. [ 1913 Webster ]

☞ 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. [ 1913 Webster ]

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. [ 1913 Webster ]