synodical month

Month Month (m[u^]nth), n. [OE. month, moneth, AS. m[=o]n[eth], m[=o]na[eth]; akin to m[=o]na moon, and to D. maand month, G. monat, OHG. m[=a]n[=o]d, Icel. m[=a]nu[eth]r, m[=a]na[eth]r, Goth. m[=e]n[=o][thorn]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. [1913 Webster]

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. [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]