sentinel

C2 Topic:General Vocabulary

US /ˈsɛn.tɪ.nəl/ UK /ˈsɛn.tɪ.nəl/ See IPA manual

Freq #19910

Meanings

1

noun
a guard or watchman posted to keep lookout

A lone sentinel stood at the gate through the night.
2

noun
a special value in a computer program that marks a boundary, ending, or exceptional condition

The parser used a null byte as a sentinel to mark the end of the string.
3

noun
a sign or indicator used to warn of a risk, disease, or important change

Public-health teams monitored sentinel cases for evidence of a wider outbreak.
4

verb
to watch over or guard

The ridge was sentineled by soldiers throughout the storm.

Verb forms

Verb forms are not available for this word yet.

Thesaurus

Synonyms

1 noun · a guard or watchman posted... sentry guard watchman lookout picket

2 noun · a special value in a... marker flagdelimiterterminatorguard value

3 noun · a sign or indicator used to... indicatorwarning signsignalearly marker

4 verb · to watch over or guard guard watch protectkeep watch over

Opposites

intruder trespasser attacker

Word family

Derived forms biosentinelnonsentinelsentinelshipsentinelwise

Related forms sentry sense sentient watch

Appears in

Phrases (1)

See all

stand sentinel
to keep watch in order to protect something

Verb + noun

Etymology

From Middle French sentinelle, from Italian sentinella, probably connected with sentire ("to feel, perceive, hear"), from Latin sentire. The computing sense keeps the idea of a watcher or marker: a value that stands guard at an important boundary.

Topics

General Vocabulary

External links

# sentinel

**Type:** Word
**Level:** C2
**Part of speech:** noun, verb
**IPA (US):** /ˈsɛn.tɪ.nəl/
**IPA (UK):** /ˈsɛn.tɪ.nəl/
**Frequency rank:** 19910

## Meanings
1. a guard or watchman posted to keep lookout
2. a special value in a computer program that marks a boundary, ending, or exceptional condition
3. a sign or indicator used to warn of a risk, disease, or important change
4. to watch over or guard

## Examples
- A lone sentinel stood at the gate through the night.
- The parser used a null byte as a sentinel to mark the end of the string.
- Public-health teams monitored sentinel cases for evidence of a wider outbreak.
- The ridge was sentineled by soldiers throughout the storm.

## Synonyms
- sentry
- guard
- watchman
- lookout
- picket
- marker
- indicator
- signal

## Antonyms
- intruder
- trespasser
- attacker

## Derived Forms
- biosentinel
- nonsentinel
- sentinelship
- sentinelwise

## Related Forms
- sentry
- sense
- sentient
- watch

## Etymology
From Middle French sentinelle, from Italian sentinella, probably connected with sentire ("to feel, perceive, hear"), from Latin sentire. The computing sense keeps the idea of a watcher or marker: a value that stands guard at an important boundary.

## Topics
- General Vocabulary

markdown