'Sidereal' definitions:

Definition of 'sidereal'

(from WordNet)
adjective
Of or relating to the stars or constellations; "sidereal bodies"; "the sidereal system"
adjective
(of divisions of time) determined by daily motion of the stars; "sidereal time" [ant: civil]

Definition of 'Sidereal'

From: GCIDE
  • Sidereal \Si*de"re*al\, a. [L. sidereus, from sidus, sideris, a constellation, a star. Cf. Sideral, Consider, Desire.]
  • 1. Relating to the stars; starry; astral; as, sidereal astronomy. [1913 Webster]
  • 2. (Astron.) Measuring by the apparent motion of the stars; designated, marked out, or accompanied, by a return to the same position in respect to the stars; as, the sidereal revolution of a planet; a sidereal day. [1913 Webster]
  • Sidereal clock, day, month, year. See under Clock, Day, etc.
  • Sideral time, time as reckoned by sideral days, or, taking the sidereal day as the unit, the time elapsed since a transit of the vernal equinox, reckoned in parts of a sidereal day. This is, strictly, apparent sidereal time, mean sidereal time being reckoned from the transit, not of the true, but of the mean, equinoctial point. [1913 Webster]

Definition of 'sidereal'

From: GCIDE
  • 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]