A4

name

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

"a4" is a 1-letter English headword indexed on PlainSpell.

The verdict

“A4” sits in 20 confusable pairs (corpus #18,471) as a proper noun. The look-alike neighbours are the real trap.

#18,471
frequency rank, English
3,931
“A” headwords
20
confusable pairs

According to Wiktionary data (CC BY-SA, analyzed September 2, 2026) - A4 class, a class of steam locomotive used on the London and North Eastern Railway.

Corpus desk

Index EN-a4 · A4 · English

A4 · rank #18,471 · 0 variants · 20 confusables

  • FREQ-MID #18,471
  • LEN-SHORT 2 letters
  • VOW-1 1 vowel
  • CONFUS-HIGH 20 pairs
  • VAR-0 0 variants
  • BOOK-MID 3,931
  • PHOTO-FINISH academies

Nearest frequency peer: academies (+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 neighbourhood for “A4”

Lower corpus rank = more everyday usage (inverted bar length for readability)

corpus weight

What this shows Bars show where “A4” sits against the nearest ranked English headwords in the FrequencyWords band, not a reprint of letter-browse containment.

Source FrequencyWords open word-frequency list As of September 2, 2026

Visual similarity to commonly confused words

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

A4 vs as
0% similar
A4 vs at
0% similar
A4 vs an
0% similar

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

Key facts for A4
PropertyValue
HeadwordA4
LanguageEnglish
Part of speechProper noun
Letters2
Frequency rank#18,471
Misspellings tracked0
Confusable pairs20
SourceWiktionary (kaikki.org)

Where “A4” 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). A4 lands here:

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

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

Easy to mix with look-alikes

The spelling risk for A4 is neighbouring look-alikes ("as", "at", …), not just typos; it is aproper noun. Frequency #18,471 among 3,931 “A” headwords. Gloss: "A4 class, a class of steam locomotive used on the London and North Eastern Railway.".

We couldn't generate a plausible misspelling set for A4, a straightforward case of a spelling with little room for common typos. It also participates in 20 confusable-pair relationships, "as", "at", "an", and more, where similar look or sound leads writers to substitute one word for another in context.

No documented word history exists for this headword, so its spelling is best read as a straightforward mapping from sound to letter. The correct English form is A4, spelled A-4.

Definition

  1. 1
    A4 class, a class of steam locomotive used on the London and North Eastern Railway.

Recorded use

Wiktionary example

These source excerpts show how A4 appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. In a letter to the author he says that when he went to King's Cross in 1936 the A4s were, and had been for some time, at a low ebb in performance.

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.

PlainSpell is rendered directly from structured Wiktionary extracts and open word-frequency lists, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of September 2, 2026. Primary sources: Wiktionary (via kaikki.org) and FrequencyWords.

Frequently Asked Questions

How do you spell "A4"?
"A4" is spelled A-4.
What does "A4" mean?
As a proper noun, "A4" means: A4 class, a class of steam locomotive used on the London and North Eastern Railway.
What words are commonly confused with "A4"?
"A4" is commonly confused with "as", "at", "an". These words look or sound similar but have different meanings. PlainSpell provides detailed comparisons for each pair.
What language does "A4" come from?
"A4" is a English word. PlainSpell covers definitions, pronunciations, and spelling data across English, Spanish, Portuguese, French, and German.
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.
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