octothorpe

/ˈɒktəʊθɔːp/

//ˈɒktəʊθɔːp// noun

"octothorpe" is a 10-letter English headword indexed on PlainSpell.

The verdict

“octothorpe” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
10
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - The hash or square symbol #, used mainly in telephony and computing.

Key facts for octothorpe
PropertyValue
Headwordoctothorpe
LanguageEnglish
Part of speechNoun
IPA/ˈɒktəʊθɔːp/
Letters10
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “octothorpe” sits in English frequency

octothorpe falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

octothorpe is uncommon English outside the top frequency list, classed as anoun, transcribed /ˈɒktəʊθɔːp/. Rarity is why readers land here mid-draft. Gloss: "The hash or square symbol #, used mainly in telephony and computing.".

The misspelling generator found no plausible variants for octothorpe, typically a sign the spelling maps closely to how the word sounds. No confusable counterpart is on file for this word, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: Origin disputed. There is no known usage before it was adopted by Bell Labs in the late 1960s or early 1970s, so most sources agree it was coined by someone at Bell Labs, but accounts from Bell Labs personnel conflict on the details. The derivation as a tra… The correct English form is octothorpe, spelled O-C-T-O-T-H-O-R-P-E.

Definition

  1. 1
    The hash or square symbol #, used mainly in telephony and computing.

Etymology

Origin disputed. There is no known usage before it was adopted by Bell Labs in the late 1960s or early 1970s, so most sources agree it was coined by someone at Bell Labs, but accounts from Bell Labs personnel conflict on the details. The derivation as a traditional term from octo- (“eight”) + thorpe (“field, hamlet or small village”) lacks any evidence, but there is near universal agreement that the first element refers to the number eight. Eight is derived from the number of ends of the lines. Thorpe could be a reference to Jim Thorpe, as one proponent was a fan of the athlete. However, it probably is just an arbitrarily-picked syllable with no particular meaning.

Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "octothorpe"?
"octothorpe" is spelled O-C-T-O-T-H-O-R-P-E. The IPA pronunciation is /ˈɒktəʊθɔːp/.
What does "octothorpe" mean?
As a noun, "octothorpe" means: The hash or square symbol #, used mainly in telephony and computing.
How do you pronounce "octothorpe"?
The IPA (International Phonetic Alphabet) transcription for "octothorpe" is /ˈɒktəʊθɔːp/. 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 "octothorpe"?
Origin disputed. There is no known usage before it was adopted by Bell Labs in the late 1960s or early 1970s, so most sources agree it was coined by someone at Bell Labs, but accounts from Bell Labs personnel conflict on the details. The derivatio... 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 “octothorpe”

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

  • The one correct English spelling is O-C-T-O-T-H-O-R-P-E - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈɒktəʊθɔːp/ (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
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