octal

/ˈɒk.təl/

//ˈɒk.təl// noun

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

"octal" is a 5-letter English headword indexed on PlainSpell.

The verdict

“octal” is uncommon English (frequency #81,642 among 15,494 “O” headwords), classed as a noun. The kind of spelling people second-guess.

#81,642
frequency rank, English
15,494
“O” headwords

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The number system that uses the eight digits 0, 1, 2, 3, 4, 5, 6, 7.

Key facts for octal
PropertyValue
Headwordoctal
LanguageEnglish
Part of speechNoun
IPA/ˈɒk.təl/
Letters5
Frequency rank#81,642
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “octal” sits in English frequency

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right). octal lands here:

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

Scale is logarithmic (each tick is 10× rarer). Source: FrequencyWords open word-frequency list.

Rare enough to double-check

octal is uncommon English at frequency #81,642 among 15,494 “O” headwords, classed as anoun, transcribed /ˈɒk.təl/. Rarity is why readers land here mid-draft. 2 senses are on record.

No misspelling variants are generated for octal in our index, and the word's spelling is regular enough that our generator found nothing worth flagging. Our confusable-pair dataset has no match for it, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.

Etymologically, the entry records: From oct- + -al. The correct English form is octal, spelled O-C-T-A-L.

Definition

  1. 1
    The number system that uses the eight digits 0, 1, 2, 3, 4, 5, 6, 7.
  2. 2
    A digit or value in the octal number system.

Etymology

From oct- + -al.

Synonyms

base 8octonary

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 "octal"?
"octal" is spelled O-C-T-A-L. The IPA pronunciation is /ˈɒk.təl/.
What does "octal" mean?
As a noun, "octal" means: The number system that uses the eight digits 0, 1, 2, 3, 4, 5, 6, 7.
How do you pronounce "octal"?
The IPA (International Phonetic Alphabet) transcription for "octal" is /ˈɒk.təl/. 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 "octal"?
From oct- + -al. 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.

Using “octal”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is O-C-T-A-L - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈɒk.təl/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Browse more English words and confusable pairs in the same reference. English words

Other uncommon English words near this rank

Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

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

Source: FrequencyWords open word-frequency list