septillion
/sɛpˈtɪljən/
"septillion" is a 10-letter English headword indexed on PlainSpell.
The verdict
“septillion” is uncommon English (outside the top frequency list), classed as a numeral. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 10
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A trillion trillion: 1 followed by 24 zeros, 10²⁴.
Corpus desk
Index EN-septillion · septillion · English
septillion · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-MEGA 10 letters
- VOW-4 4 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "S" thin
- PHOTO-UNK Peer pending
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.
| Property | Value |
|---|---|
| Headword | septillion |
| Language | English |
| Part of speech | Numeral |
| IPA | /sɛpˈtɪljən/ |
| Letters | 10 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “septillion” in English
Rare enough to double-check
septillion is uncommon English outside the top frequency list, classed as anumeral, transcribed /sɛpˈtɪljən/. Rarity is why readers land here mid-draft. 2 senses are on record.
septillion doesn't appear in our generated misspelling index, and the word's spelling is regular enough that our generator found nothing worth flagging. No confusable counterpart is on file for this word, which tends to mean the word is visually distinctive enough to stand on its own.
Etymologically, the entry records: From French septillion, from sept- (“seven”) + -illion. By surface analysis, sept- + -illion. The correct English form is septillion, spelled S-E-P-T-I-L-L-I-O-N.
Definition
- 1A trillion trillion: 1 followed by 24 zeros, 10²⁴.
- 2A billion quintillion: 1 followed by 42 zeros, 10⁴².
Etymology
From French septillion, from sept- (“seven”) + -illion. By surface analysis, sept- + -illion.
Synonyms
This word in other languages
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.