fly

/flaɪ/

//flaɪ// noun

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

"fly" is a 3-letter English headword indexed on PlainSpell.

The verdict

“fly” is a regularly-used English word, ranked #1,827 in English word frequency and used as a noun.

#1,827
frequency rank, English
3
letters
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Any insect of the order Diptera; characterized by having two wings (except for some wingless species), also called true flies.

Visual similarity to commonly confused words

How many letter changes separate each confused pair (Levenshtein distance, normalized).

fly vs FM
0% similar
fly vs fu
33% similar
fly vs fo
33% similar

Source: PlainSpell confusable corpus (Wiktionary, CC BY-SA).

Key facts for fly
PropertyValue
Headwordfly
LanguageEnglish
Part of speechNoun
IPA/flaɪ/
Letters3
Frequency rank#1,827
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “fly” 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). fly lands here:

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

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

Spelling & Dictionary Insight

The English entry for fly is 3 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /flaɪ/. Corpus data places it at rank #1,827 in overall English word frequency, indicating it appears regularly in written and spoken text. Wiktionary records 10 distinct senses for this headword, so context determines which meaning a reader should apply.

Our edit-distance generator produced no likely misspellings for fly, typically a sign the spelling maps closely to how the word sounds. It also participates in 20 confusable-pair relationships, "FM", "fu", "fo", and more, a pairing that trips writers up because the two words share enough sound or shape to blur together.

Etymologically, the entry records: From Middle English flye, flie, from Old English flȳġe, flēoge (“a fly”), from Proto-West Germanic *fleugā, from Proto-Germanic *fleugǭ (“a fly”), from Proto-Indo-European *plewk- (“to fly”). Cognate with Scots flee, Saterland Frisian Fljooge, Dutch vlieg, … The correct English form is fly, spelled F-L-Y.

Definition

  1. 1
    Any insect of the order Diptera; characterized by having two wings (except for some wingless species), also called true flies.
  2. 2
    Especially, any of the insects of the family Muscidae, such as the common housefly (other families of Diptera include mosquitoes and midges).
  3. 3
    Any similar but not closely related insect, such as a dragonfly, butterfly, or gallfly.
  4. 4
    A lightweight fishing lure resembling an insect.
  5. 5
    A chest exercise performed by moving extended arms from the sides to in front of the chest. (also flye)
  6. 6
    The butterfly stroke (plural is normally flys).
  7. 7
    A witch's familiar.
  8. 8
    A parasite.
  9. 9
    A simple dance in which the hands are shaken in the air, popular in the 1960s.
  10. 10
    A butterfly (combination of four options).

Etymology

From Middle English flye, flie, from Old English flȳġe, flēoge (“a fly”), from Proto-West Germanic *fleugā, from Proto-Germanic *fleugǭ (“a fly”), from Proto-Indo-European *plewk- (“to fly”). Cognate with Scots flee, Saterland Frisian Fljooge, Dutch vlieg, German Low German Fleeg, German Fliege, Danish flue, Norwegian Bokmål flue, Norwegian Nynorsk fluge, Swedish fluga, Icelandic fluga.

This word in other languages

mosco(Español)mouche(Français)Fliege(Deutsch)

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 "fly"?
"fly" is spelled F-L-Y. The IPA pronunciation is /flaɪ/.
What does "fly" mean?
As a noun, "fly" means: Any insect of the order Diptera; characterized by having two wings (except for some wingless species), also called true flies.
What words are commonly confused with "fly"?
"fly" is commonly confused with "FM", "fu", "fo". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "fly"?
The IPA (International Phonetic Alphabet) transcription for "fly" is /flaɪ/. 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 "fly"?
From Middle English flye, flie, from Old English flȳġe, flēoge (“a fly”), from Proto-West Germanic *fleugā, from Proto-Germanic *fleugǭ (“a fly”), from Proto-Indo-European *plewk- (“to fly”). Cognate with Scots flee, Saterland Frisian Fljooge, Dut... 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 “fly”

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

  • The one correct English spelling is F-L-Y - every other letter order is a misspelling in standard orthography.
  • Say it as /flaɪ/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “FM” - see the side-by-side comparison. fly vs FM
  • 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 FrequencyWords open word-frequency list