flash mob

noun

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

The verdict

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

Unranked
below top-frequency English
9
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A group of people who rapidly assemble, perform an unusual and seemingly pointless act, and then quickly disperse.

Corpus desk

Index EN-flash-mob · flash mob · English

flash mob · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-LONG 9 letters
  • VOW-2 2 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-THIN "F" 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.

Key facts for flash mob
PropertyValue
Headwordflash mob
LanguageEnglish
Part of speechNoun
Letters9
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “flash mob” in English

flash mobranks outside the top 100,000 English headwords, in the long tail of specialist, archaic, or seldom-used vocabulary, exactly the territory where a reader stops mid-sentence to double-check spelling.

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

Rare enough to double-check

flash mob is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. Gloss: "A group of people who rapidly assemble, perform an unusual and seemingly pointless act, and then quickly disperse.".

The misspelling generator found no plausible variants for flash mob, and the word's spelling is regular enough that our generator found nothing worth flagging. We don't track a confusable pairing for this entry, since its spelling is unusual enough that it doesn't cluster with a lookalike.

Etymologically, the entry records: Perhaps from flash crowd, a term coined by Larry Niven in Flash Crowd (1973), a story about cheap teleportation in the future. The correct English form is flash mob, spelled F-L-A-S-H- -M-O-B.

Definition

  1. 1
    A group of people who rapidly assemble, perform an unusual and seemingly pointless act, and then quickly disperse.

Recorded use

Wiktionary example

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

  1. Called into being on short notice by Web sites and e-mail distribution lists, flash mobs meet at an appointed time, engage in some organized spontaneity for a few minutes, then rapidly disperse. The activities are innocent, if mysterious, and tend to bring together loose groupings of surprisingly conventional looking young adults.

Etymology

Perhaps from flash crowd, a term coined by Larry Niven in Flash Crowd (1973), a story about cheap teleportation in the future.

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.

Frequently Asked Questions

How do you spell "flash mob"?
"flash mob" is spelled F-L-A-S-H- -M-O-B.
What does "flash mob" mean?
As a noun, "flash mob" means: A group of people who rapidly assemble, perform an unusual and seemingly pointless act, and then quickly disperse.
What is the origin of the word "flash mob"?
Perhaps from flash crowd, a term coined by Larry Niven in Flash Crowd (1973), a story about cheap teleportation in the future. 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.

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

Source: FrequencyWords open word-frequency list