sennight

/ˈsɛnaɪt/

//ˈsɛnaɪt// noun

"sennight" is a 8-letter English headword indexed on PlainSpell.

The verdict

“sennight” 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
8
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - A period of seven consecutive days and nights; a week.

Key facts for sennight
PropertyValue
Headwordsennight
LanguageEnglish
Part of speechNoun
IPA/ˈsɛnaɪt/
Letters8
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “sennight” sits in English frequency

sennight 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 sennight is 8 letters long, classified as a noun, and transcribed in the International Phonetic Alphabet as /ˈsɛnaɪt/. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. Wiktionary records 4 distinct senses for this headword, so context determines which meaning a reader should apply.

sennight doesn't appear in our generated misspelling index, a straightforward case of a spelling with little room for common typos. Our confusable-pair dataset has no match for it, since no other headword is close enough in sound or shape to pair with it.

Etymologically, the entry records: From Middle English senight, senyght, sinight (“seven days or nights, a week”) [and other forms], a shortened form of seven-night, sevenight, sevenyght [and other forms], from Late Old English seofeniht (compare seofonnihte (“seven days old; seven days long… The correct English form is sennight, spelled S-E-N-N-I-G-H-T.

Definition

  1. 1
    A period of seven consecutive days and nights; a week.
  2. 2
    Preceded by a specified day such as Sunday, today, or yesterday: a week from (either before or after) the specified day.
  3. 3
    Preceded by a specified day and come: a week after the specified day.
  4. 4
    Preceded by a specified day and gone or was: a week before the specified day.

Etymology

From Middle English senight, senyght, sinight (“seven days or nights, a week”) [and other forms], a shortened form of seven-night, sevenight, sevenyght [and other forms], from Late Old English seofeniht (compare seofonnihte (“seven days old; seven days long”, adjective)), from seofon (“seven”) (ultimately from Proto-Indo-European *septḿ̥ (“seven”)) + niht (“night; day (when computing spans of time)”) (ultimately from Proto-Indo-European *nókʷts (“night”)). Doublet of sevennight.

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 "sennight"?
"sennight" is spelled S-E-N-N-I-G-H-T. The IPA pronunciation is /ˈsɛnaɪt/.
What does "sennight" mean?
As a noun, "sennight" means: A period of seven consecutive days and nights; a week.
How do you pronounce "sennight"?
The IPA (International Phonetic Alphabet) transcription for "sennight" is /ˈsɛnaɪt/. Click the speaker icon on the pronunciation badge above to hear it spoken aloud where audio is available.
What is the origin of the word "sennight"?
From Middle English senight, senyght, sinight (“seven days or nights, a week”) [and other forms], a shortened form of seven-night, sevenight, sevenyght [and other forms], from Late Old English seofeniht (compare seofonnihte (“seven days old; seven... 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 “sennight”

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

  • The one correct English spelling is S-E-N-N-I-G-H-T - every other letter order is a misspelling in standard orthography.
  • Say it as /ˈsɛnaɪt/ (IPA); tap the speaker on the pronunciation badge to hear it where audio exists.
  • 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