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sentinel

/ˈsɛn.tɪ.nəl/noun, verb

sentinel is spelled S-E-N-T-I-N-E-L. The wrong spelling people search most is sentinal: about 1,080 Bing searches a month in the United States (September 2025 to August 2026), about 1 in 10 of all searches for the word. Sentinel is a noun meaning “A sentry, watch, or guard”. The plural of sentinel is sentinels.

How many letters and syllables are in sentinel?

Letters8: S-E-N-T-I-N-E-L
Syllables3 (from its American pronunciation)
In writing2.6 times per million words; the 16,896th most frequent word form
Wrong spellings searched1; the most searched, sentinal, about 1,080 Bing searches a month (all of them)

Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media); Bing searches in the United States: the average month from September 2025 to August 2026 (Microsoft Advertising keyword data through DataForSEO, read September 30, 2026).

How do you spell sentinel?

Sentinel is spelled S-E-N-T-I-N-E-L. One wrong spelling is searched or written often enough to measure; together they are about 1 in 10 of the searches for sentinel in either form.

sentinelthe right spelling9,580 searches a month
sentinala in place of e1,080 searches a month

Bing searches in the United States: the average month from September 2025 to August 2026 (Microsoft Advertising keyword data through DataForSEO, read September 30, 2026). Wrong spellings are taken from Wiktionary entries tagged "misspelling" and its obsolete or nonstandard forms, Wikipedia's Lists of common misspellings and the codespell dictionary, then measured. The proofreader's marks show the change that corrects each one.

How common is sentinel?

Sentinel appears 2.6 times per million words in written English, the 16,896th most frequent word form in the list.

Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

How do you pronounce sentinel?

  • /ˈsɛn.tɪ.nəl/

Sentinel has 3 syllables (counted from its American pronunciation in the CMU Pronouncing Dictionary).

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-us-sentinel.ogg, Wikimedia Commons (author and licence on each file's page).

Forms of sentinel

  • sentinels plural, present, singular, he/she/it
  • sentineling US, participle, present
  • sentinelling UK, participle, present
  • sentineled US, participle, past
  • sentinelled UK, participle, past

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

What does sentinel mean?

The meanings the English Wiktionary records, quoted as written there (source below).

noun

  1. 1

    A sentry, watch, or guard.

  2. 2

    obsoleteA private soldier.

  3. 3

    A unique value recognised by a computer program for processing in a special way, or marking the end of a set of data.

    The <xmp> tag is a sentinel that suspends web-page processing and displays the subsequent text literally

  4. 4

    A sentinel crab.

  5. 5

    A sign of a health risk (e.g. a disease, an adverse effect).

    sentinel animals can be used to explore endemic diseases.

verb

  1. 1

    To watch over as a guard.

    He sentineled the north wall.

  2. 2

    To post a guard for.

    He sentineled the north wall with just one man.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

Sentinel in Spanish, French, German and Portuguese

LanguageWords
Frenchfactionnaire, sentinelle (a sentry or guard), regarder (To watch over something as a guard)
GermanWache, Wachposten, Wächter, Wächterin (a sentry or guard), Markierung, Schlüsselwort (a unique phrase of characters)
Portuguesesentinela, vigia (a sentry or guard), vigiar (To watch over something as a guard)
Spanishcentinela (a sentry or guard)

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.

Where does sentinel come from?

First attested in the 1570s from Middle French sentinelle (“watch or guard kept by a soldier”), from Old Italian sentinella, probably from sentina + -ella, from sentire (“perceive, watch, hear”), from sentiō (“feel, perceive by the senses”). See also sense, sentient.

Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).

What to look up after sentinel