fo

noun

"fo" is a 2-letter English headword indexed on PlainSpell.

The verdict

“fo” sits in 20 confusable pairs (corpus #12,049) as a noun. The look-alike neighbours are the real trap.

#12,049
frequency rank, English
2,507
“F” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - Abbreviation of folio, page and book size (10"-12.5" x 15"-20").

Corpus desk

Index EN-fo · fo · English

fo · rank #12,049 · 0 variants · 20 confusables

  • FREQ-MID #12,049
  • LEN-SHORT 2 letters
  • VOW-1 1 vowel
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-MID 2,507
  • PHOTO-FINISH flipped

Nearest frequency peer: flipped (-1 rank slots)

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.

Frequency neighbours of confusable “fo”

Peers at similar corpus weight, separate from look-alike pairs below

corpus weight

What this shows Bars place “fo” against nearest ranked English headwords, not a reprint of the confusable-pair desk.

Source FrequencyWords open word-frequency list As of September 3, 2026

Visual similarity to commonly confused words

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

fo vs fu
50% similar
fo vs FS
0% similar
fo vs FP
0% similar

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

Key facts for fo
PropertyValue
Headwordfo
LanguageEnglish
Part of speechNoun
Letters2
Frequency rank#12,049
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Corpus rank beside confusables of “fo”

Word frequency stretches from the small set of words we reach for constantly (left) out to the long tail barely used once in a while (right).folands here:

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

Scale is logarithmic (each tick is 10× rarer). Same rarity band neighbours include “flipped” (#12,048), “formidable” (#12,050), “fishermen” (#12,047). Among 2,507 “F” headwords, “fo” is #12,049. Source: FrequencyWords open word-frequency list.

Easy to mix with look-alikes

The spelling risk for fo is neighbouring look-alikes ("fu", "FS", …), not just typos; it is anoun. Frequency #12,049 among 2,507 “F” headwords. Gloss: "Abbreviation of folio, page and book size (10"-12.5" x 15"-20").".

Zero misspellings are on record for fo in our index, a sign its spelling follows regular English conventions. It also participates in 20 confusable-pair relationships, "fu", "FS", "FP", and more, since the words sound or look close enough that writers reach for the wrong one mid-sentence.

Etymologically, the entry records: Clipping of folio. The correct English form is fo, spelled F-O.

Definition

  1. 1
    Abbreviation of folio, page and book size (10"-12.5" x 15"-20").

Etymology

Clipping of folio.

Synonyms

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 "fo"?
"fo" is spelled F-O.
What does "fo" mean?
As a noun, "fo" means: Abbreviation of folio, page and book size (10"-12.5" x 15"-20").
What words are commonly confused with "fo"?
"fo" is commonly confused with "fu", "FS", "FP". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
What is the origin of the word "fo"?
Clipping of folio. 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