diagonal mark

noun

"diagonal-mark" is a 12-letter English headword indexed on PlainSpell.

The verdict

“diagonal mark” is outside the top-ranked English vocabulary, used as a noun - the kind of word writers most often double-check.

Unranked
below top-frequency English
13
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Synonym of slash as the forward slash ⟨/⟩ and sometimes also its proscribed sense inclusive of the backslash ⟨\⟩.

Key facts for diagonal mark
PropertyValue
Headworddiagonal mark
LanguageEnglish
Part of speechNoun
Letters13
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “diagonal mark” sits in English frequency

diagonal mark falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

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

Spelling & Dictionary Insight

The English entry for diagonal mark is 13 letters long, classified as a noun. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. The dominant gloss from Wiktionary reads: "Synonym of slash as the forward slash ⟨/⟩ and sometimes also its proscribed sense inclusive of the backslash ⟨\⟩.".

diagonal mark doesn't appear in our generated misspelling index, typically a sign the spelling maps closely to how the word sounds. It is not paired with a close-neighbour confusable in our dataset, since nothing in our dataset looks or sounds close enough to cause mix-ups.

Etymologically, the entry records: To distinguish the intended sense of diagonal. The correct English form is diagonal mark, spelled D-I-A-G-O-N-A-L- -M-A-R-K.

Definition

  1. 1
    Synonym of slash as the forward slash ⟨/⟩ and sometimes also its proscribed sense inclusive of the backslash ⟨\⟩.

Etymology

To distinguish the intended sense of diagonal.

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 "diagonal mark"?
"diagonal mark" is spelled D-I-A-G-O-N-A-L- -M-A-R-K.
What does "diagonal mark" mean?
As a noun, "diagonal mark" means: Synonym of slash as the forward slash ⟨/⟩ and sometimes also its proscribed sense inclusive of the backslash ⟨\⟩.
What is the origin of the word "diagonal mark"?
To distinguish the intended sense of diagonal. 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 “diagonal mark”

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

  • The one correct English spelling is D-I-A-G-O-N-A-L- -M-A-R-K - every other letter order is a misspelling in standard orthography.
  • 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