sidereal

/saɪˈdɪə.ɹi.əl/

//saɪˈdɪə.ɹi.əl// adj

By · According to Wiktionary data (CC BY-SA) ·

"sidereal" is a 8-letter English headword indexed on PlainSpell.

The verdict

“sidereal” is uncommon English (frequency #74,505 among 6,566 “S” headwords), classed as an adjective. The kind of spelling people second-guess.

#74,505
frequency rank, English
6,566
“S” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Of or relating to the stars.

Corpus desk

Index EN-sidereal · sidereal · English

sidereal · rank #74,505 · 0 variants · 0 confusables

  • FREQ-RARE #74,505
  • LEN-LONG 8 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-DENSE 6,566
  • PHOTO-FINISH shul

Nearest frequency peer: shul (-3 rank slots)

Read with this headword: Spelling guide for this pattern

Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.

Long-tail ranks near “sidereal”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “sidereal” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for sidereal
PropertyValue
Headwordsidereal
LanguageEnglish
Part of speechAdjective
IPA/saɪˈdɪə.ɹi.əl/
Letters8
Frequency rank#74,505
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “sidereal” in English

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).siderealfalls in this rarity band:

#1#100#1K#10K#100K
← used constantlyrarely used →

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “shul” (#74,502), “simples” (#74,509), “singleness” (#74,510). Among 6,566 “S” headwords, “sidereal” is #74,505. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

sidereal is uncommon English at frequency #74,505 among 6,566 “S” headwords, classed as anadjective, transcribed /saɪˈdɪə.ɹi.əl/. Rarity is why readers land here mid-draft. 3 senses are on record.

We couldn't generate a plausible misspelling set for sidereal, which points to an orthography that plays by predictable English rules. Our confusable-pair dataset has no match for it, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From Latin sīdereus + -al (cf. Latin sīderālis), from sīdus (“star, constellation”), of unknown ultimate origin, likely a substrate language such as Pre-Greek. The correct English form is sidereal, spelled S-I-D-E-R-E-A-L.

Definition

  1. 1
    Of or relating to the stars.
  2. 2
    Relating to a measurement of time relative to the position of the stars.
  3. 3
    Relating to a measurement of time relative to the point of the vernal equinox.

Recorded use

Wiktionary examples

These source excerpts show how sidereal appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. These fringes of lamplight, struggling up through smoke and thousandfold exhalation, some fathoms into the ancient reign of Night, what thinks Boötes of them, as he leads his Hunting-Dogs over the Zenith in their leash of sidereal fire?
  2. The field of sidereal astronomy, therefore, was virtually untrodden when, shortly after the beginning of his telescopic work, Herschel began his first review of the heavens.

Etymology

From Latin sīdereus + -al (cf. Latin sīderālis), from sīdus (“star, constellation”), of unknown ultimate origin, likely a substrate language such as Pre-Greek.

This word in other languages

sidéral(Français)siderisch(Deutsch)sideral(Português)

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA); frequency ordering uses the FrequencyWords open word-frequency list (2018 English corpus, MIT). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "sidereal"?
"sidereal" is spelled S-I-D-E-R-E-A-L. The IPA pronunciation is /saɪˈdɪə.ɹi.əl/.
What does "sidereal" mean?
As an adjective, "sidereal" means: Of or relating to the stars.
How do you pronounce "sidereal"?
The IPA (International Phonetic Alphabet) transcription for "sidereal" is /saɪˈdɪə.ɹi.əl/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "sidereal"?
From Latin sīdereus + -al (cf. Latin sīderālis), from sīdus (“star, constellation”), of unknown ultimate origin, likely a substrate language such as Pre-Greek. See the full etymology section above for more details.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "sidereal", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 8 letters (nearest by frequency rank).

Sharples#74,498slovenly#74,517snipping#74,520snowmelt#74,521

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list