- Also called calendar month. any of the twelve parts, as January or February, into which the calendar year is divided.
- the time from any day of one calendar month to the corresponding day of the next.
- a period of four weeks or 30 days.
- Also called solar month. one-twelfth of a solar or tropical year.
- Also called lunar month. the period of a complete revolution of the moon around the earth, as the period between successive new moons (synodic month), equal to 29.531 days, or the period between successive conjunctions with a star (sidereal month), equal to 27.322 days, or the period between successive perigees (anomalistic month), equal to 27.555 days, or the period between successive similar nodes (nodical month or draconic month), equal to 27.212 days.
- an unusually long period of time of indefinite length: I haven't seen him for months.
- a month of Sundays. Sunday1(def 4).
Origin of month
- See month (def. 4)
- one of the twelve divisions (calendar months) of the calendar year
- a period of time extending from one date to a corresponding date in the next calendar month
- a period of four weeks or of 30 days
- the period of time (tropical month) taken by the moon to return to the same longitude after one complete revolution around the earth; 27.321 58 days (approximately 27 days, 7 hours, 43 minutes, 4.5 seconds)
- the period of time (sidereal month) taken by the moon to make one complete revolution around the earth, measured between two successive conjunctions with a distant star; 27.321 66 days (approximately 27 days, 7 hours, 43 minutes, 11 seconds)
- Also called: lunation the period of time (lunar or synodic month) taken by the moon to make one complete revolution around the earth, measured between two successive new moons; 29.530 59 days (approximately 29 days, 12 hours, 44 minutes, 3 seconds)
- a month of Sundays informal a long unspecified period
Word Origin for month
Old English monað, from Proto-Germanic *menoth- (cf. Old Saxon manoth, Old Frisian monath, Middle Dutch manet, Dutch maand, Old High German manod, German Monat, Old Norse manaðr, Gothic menoþs "month"), related to *menon- "moon" (see moon (n.); the month was calculated from lunar phases). Its cognates mean only "month" in the Romance languages, but in Germanic generally continue to do double duty. Phrase a month of Sundays "a very long time" is from 1832 (roughly 7 and a half months, but never used literally).
- See under solar time.
In addition to the idiom beginning with month
- month of Sundays, a
- by the day (month)
- (for months) on end