subdomain

noun

"subdomain" is a 9-letter English headword indexed on PlainSpell.

The verdict

“subdomain” is uncommon English (frequency #86,804 among 6,566 “S” headwords), classed as a noun. The kind of spelling people second-guess.

#86,804
frequency rank, English
6,566
“S” headwords

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - A domain or sphere that is part of a larger domain or sphere.

Corpus desk

Index EN-subdomain · subdomain · English

subdomain · rank #86,804 · 0 variants · 0 confusables

  • FREQ-RARE #86,804
  • LEN-LONG 9 letters
  • VOW-4 4 vowels
  • CONFUS-0 No pairs
  • VAR-0 0 variants
  • BOOK-DENSE 6,566
  • PHOTO-FINISH Suda

Nearest frequency peer: Suda (+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.

Long-tail ranks near “subdomain”

Sparse band: bars invert rank so rarer forms read shorter

corpus weight

What this shows Long-tail view: where “subdomain” sits against similarly uncommon English ranks.

Source FrequencyWords open word-frequency list As of September 3, 2026
Key facts for subdomain
PropertyValue
Headwordsubdomain
LanguageEnglish
Part of speechNoun
Letters9
Frequency rank#86,804
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “subdomain” in English

Every-word frequency runs from the handful of words we use constantly (left) to the long tail used once in a blue moon (right).subdomainfalls in this rarity band:

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

Ticks step logarithmically, so each one marks a roughly tenfold drop in how often the word turns up. Rare peers in the same band: “Suda” (#86,805), “subacute” (#86,802), “Sule” (#86,806). Among 6,566 “S” headwords, “subdomain” is #86,804. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

subdomain is uncommon English at frequency #86,804 among 6,566 “S” headwords, classed as anoun. Rarity is why readers land here mid-draft. 3 senses are on record.

Zero misspellings are on record for subdomain in our index, and the word's spelling is regular enough that our generator found nothing worth flagging. This entry stands alone in our confusable dataset, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.

Etymologically, the entry records: From sub- + domain. The correct English form is subdomain, spelled S-U-B-D-O-M-A-I-N.

Definition

  1. 1
    A domain or sphere that is part of a larger domain or sphere.
  2. 2
    A domain name that has been prefaced with additional parts separated with periods.
  3. 3
    An additional part prefaced to a domain name.

Recorded use

Wiktionary examples

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

  1. As a technical subdomain of biology ecological investigations have evolved from what has been traditionally called natural history.
  2. A domain is a subdomain of another domain if it is contained within that domain. This relationship can be tested by seeing if the subdomain's name ends with the containing domain's name. For example, A.B.C.D is a subdomain of B.C.D, C.D, D, and " ".

Etymology

From sub- + domain.

Synonyms

unqualified hostname

This word in other languages

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 "subdomain"?
"subdomain" is spelled S-U-B-D-O-M-A-I-N.
What does "subdomain" mean?
As a noun, "subdomain" means: A domain or sphere that is part of a larger domain or sphere.
What is the origin of the word "subdomain"?
From sub- + domain. 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.

Similar English words by spelling shape

Same letter count and similar misspelling depth for "subdomain", not the corpus desk frequency band.

Same letter count

Frequency-ranked English headwords with 9 letters (nearest by frequency rank).

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list