deep sleep

noun

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

The verdict

“deep sleep” is uncommon English (outside the top frequency list), classed as a noun. The kind of spelling people second-guess.

Unranked
below top-frequency English
10
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - Used other than figuratively or idiomatically: see deep, sleep.

Key facts for deep sleep
PropertyValue
Headworddeep sleep
LanguageEnglish
Part of speechNoun
Letters10
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “deep sleep” sits in English frequency

deep sleep 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.

Rare enough to double-check

deep sleep is uncommon English outside the top frequency list, classed as anoun. Rarity is why readers land here mid-draft. 3 senses are on record.

deep sleep has no tracked misspelling variants, a straightforward case of a spelling with little room for common typos. No close-neighbour confusable shows up for this headword in our dataset, suggesting its spelling stands apart enough that readers rarely confuse it with something else.

This entry carries no recorded etymology, so any spelling logic here comes from how the word's sounds map to letters, not a documented origin story. The correct English form is deep sleep, spelled D-E-E-P- -S-L-E-E-P.

Definition

  1. 1
    Used other than figuratively or idiomatically: see deep, sleep.
  2. 2
    stage 3 of non-rapid eye movement sleep
  3. 3
    Artificially induced hibernation in humans for the purpose of long distance space travel.

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). See the methodology for how each field is sourced and updated.

Frequently Asked Questions

How do you spell "deep sleep"?
"deep sleep" is spelled D-E-E-P- -S-L-E-E-P.
What does "deep sleep" mean?
As a noun, "deep sleep" means: Used other than figuratively or idiomatically: see deep, sleep.
What language does "deep sleep" come from?
"deep sleep" 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.

Using “deep sleep”

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

  • The one correct English spelling is D-E-E-P- -S-L-E-E-P - 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