fathom

/ˈfað(ə)m/

//ˈfað(ə)m// noun

"fathom" is a 6-letter English headword indexed on PlainSpell.

The verdict

“fathom” is a moderately-common English word, ranked #20,922 in English word frequency and used as a noun.

#20,922
frequency rank, English
6
letters
9
tracked misspellings
2
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A man's armspan, generally reckoned to be six feet (about 1.8 metres). Later used to measure the depth of water, but now generally replaced by the metre outside American usage.

Visual similarity to commonly confused words

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

fathom vs father
67% similar
fathom vs fandom
67% similar

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

Key facts for fathom
PropertyValue
Headwordfathom
LanguageEnglish
Part of speechNoun
IPA/ˈfað(ə)m/
Letters6
Frequency rank#20,922
Misspellings tracked9
Confusable pairs2
SourceWiktionary (kaikki.org)

Where “fathom” 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). fathom 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 fathom is 6 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈfað(ə)m/. Corpus data places it at rank #20,922 in overall English word frequency, marking it as uncommon enough that many writers pause before typing it. Wiktionary records 8 distinct senses for this headword, so context determines which meaning a reader should apply.

Our generated misspelling index lists 9 likely wrong-spelling variants for fathom, with forms such as "afthom", "fahtom", and "fathhom". Each of these forms differs from the correct spelling by one small edit: a doubled letter, a dropped silent letter, or a substituted vowel. It also participates in 2 confusable-pair relationships, "father", "fandom", since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Etymologically, the entry records: From Middle English fathome, fadom, fadme (“unit of length of about six feet; depth of six feet for nautical soundings; (loosely) cubit; ell”) [and other forms], from Old English fæþm, fæþme (“encircling or outstretched arms, bosom, embrace; envelopment; co… The correct English form is fathom, spelled F-A-T-H-O-M.

Definition

  1. 1
    A man's armspan, generally reckoned to be six feet (about 1.8 metres). Later used to measure the depth of water, but now generally replaced by the metre outside American usage.
  2. 2
    A man's armspan, generally reckoned to be six feet (about 1.8 metres). Later used to measure the depth of water, but now generally replaced by the metre outside American usage.
  3. 3
    A measure of distance to shore: the nearest point to shore at which the water depth is the value quoted.
  4. 4
    An unspecified depth.
  5. 5
    Depth of insight; mental reach or scope.
  6. 6
    The act of stretching out one's arms away from the sides of the torso so that they make a straight line perpendicular to the body.
  7. 7
    Someone or something that is embraced.
  8. 8
    Control, grasp.

Etymology

From Middle English fathome, fadom, fadme (“unit of length of about six feet; depth of six feet for nautical soundings; (loosely) cubit; ell”) [and other forms], from Old English fæþm, fæþme (“encircling or outstretched arms, bosom, embrace; envelopment; control, grasp, power; fathom (unit of measurement); cubit”) [and other forms], from Proto-West Germanic *faþm (“outstretched arms, embrace; fathom (unit of measurement)”), from Proto-Germanic *faþmaz (“outstretched arms, embrace; fathom (unit of measurement)”), from Proto-Indo-European *pet-, *peth₂- (“to spread out; to fly”). Cognates * Ancient Greek πέταλος (pétalos, “broad; flat”), πετᾰ́ννῡμῐ (petắnnūmĭ, “to open; to spread out; to be dispersed or scattered”) (whence English petal) * Gothic 𐍆𐌰𐌸𐌰 (faþa, “fench; hedge”) * Latin pateō (“to extend, increase; to be accessible, attainable, open; to be exposed, vulnerable”) * Low German fadem, faem (“cubit; thread”) * Middle Dutch vadem (modern Dutch vaam, vadem (“fathom”)) * Norwegian Bokmål favn (“an embrace; a fathom”) * Old Frisian fethm (“outstretched arms”) * Old High German fadam, fadum (“cubit”) (Middle High German vade (“enclosure”), vadem, vaden, modern German Faden (“fathom; filament, thread”)) * Old Norse faþmr (Danish favn (“an embrace; a fathom”), Icelandic faðmur (“an embrace”), Swedish famn (“the arms, bosom; an embrace”)) * Old Welsh etem (“thread”)

Synonyms

This word in other languages

Common misspellings

Also misspelled as: afthom,fahtom,fathhom,fathmo,fathomm,fatohm,fatthom,ffathom,ftahom

Misspelling Pattern Breakdown

How far each generated variant is from the correct spelling of fathom - measured in single-character edits (insert, delete, or substitute a letter). Larger bars are easier to catch; one-edit slips are the sneakiest.

afthom2fahtom2fathhom1fathmo2fathomm1fatohm2fatthom1ffathom1
Edit distance from "fathom"

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 "fathom"?
"fathom" is spelled F-A-T-H-O-M. The IPA pronunciation is /ˈfað(ə)m/.
What does "fathom" mean?
As a noun, "fathom" means: A man's armspan, generally reckoned to be six feet (about 1.8 metres). Later used to measure the depth of water, but now generally replaced by the metre outside American usage.
What words are commonly confused with "fathom"?
"fathom" is commonly confused with "father", "fandom". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
How do you pronounce "fathom"?
The IPA (International Phonetic Alphabet) transcription for "fathom" is /ˈfað(ə)m/. 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 "fathom"?
From Middle English fathome, fadom, fadme (“unit of length of about six feet; depth of six feet for nautical soundings; (loosely) cubit; ell”) [and other forms], from Old English fæþm, fæþme (“encircling or outstretched arms, bosom, embrace; envel... 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 “fathom”

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

  • The one correct English spelling is F-A-T-H-O-M - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈfað(ə)m/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • Don't mix it up with “father” - see the side-by-side comparison. fathom vs father
  • 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