sidereal

[ sahy-deer-ee-uhl ]

adjective

, Astronomy.

1. determined by or from the stars:

   sidereal time.

2. of or relating to the stars.

sidereal

/ saɪˈdɪərɪəl /

adjective

1. of, relating to, or involving the stars
2. determined with reference to one or more stars

   the sidereal day

sidereal

/ sī-dîr′ē-əl /

1. Relating to the stars or constellations.
2. Measured with respect to the background of fixed stars instead of the Sun.

Derived Forms

• siˈdereally, adverb

Other Words From

• si·dere·al·ly adverb
• nonsi·dere·al adjective
• unsi·dere·al adjective

Word History and Origins

Origin of sidereal¹

1625–35; < Latin sīdere ( us ) of, belonging to the stars ( sīder-, stem of sīdus star, constellation + -eus adj. suffix) + -al ¹

Word History and Origins

Origin of sidereal¹

C17: from Latin sīdereus, from sīdus a star, a constellation

Example Sentences

And Sideræl — pronounced “sigh-deer-ee-el” — is “a more elven” spelling of sidereal, “the true time of the universe, star time, deep space time, not our relative earth time,” she explained.

From Seattle Times

I mean, it still feels like fall, by the rhythm of the sidereal calendar I had imprinted in me by Sid and Marty Krofft.

From New York Times

Despite these shortcomings, Price identified a gear train—a set of linked gears—that calculated the average position of the moon on any specific date by using its period relation of 254 sidereal rotations in 19 years.

From Scientific American

Livio structures his account partly around specific works, including Galileo’s 1610 The Sidereal Messenger, which described his major astronomical observations.

From Nature

That’s where Mercer’s triumph manifests itself, there at the end of the great sidereal cycle.

From Literature

Related Words

• glittering
• luminous
• sparkling
• stellar