monitor

American  

[mon-i-ter] / ˈmɒn ɪ tər /

noun

• monitors
  plural

1. (especially formerly) a student appointed to assist in the conduct of a class or school, as to help take attendance or keep order.

2. a person appointed to supervise students, applicants, etc., taking an examination, chiefly to prevent cheating; proctor.

3. a person who admonishes, especially with reference to conduct.

4. something that serves to remind or give warning.

5. a device or arrangement for observing, detecting, or recording the operation of a machine or system, especially an automatic control system.

6. an instrument for detecting dangerous gases, radiation, etc.

7. Radio and Television.

   1. a receiving apparatus used in a control room, especially to provide a steady check of the quality of an audio or video transmission.

   2. a similar apparatus placed in various parts of a studio so that an audience can watch a recorded portion of a show, the performer can see the various segments of a program, etc.

   3. any such receiving apparatus used in a closed-circuit system, as in an operating room.

8. Computers.

   1. the screen component of a computer, especially a free-standing screen.

   2. a control program.

   3. a group of systems used to measure the performance of a computer system.

9. Nautical.

   1. a former U.S. steam-propelled, armored warship of very low freeboard, having one or more turrets and used for coastal defense.

   2. (initial capital letter, italics) the first of such warships, used against the Confederate ironclad warship Merrimac at Hampton Roads, Va., in 1862.

10. a raised construction straddling the ridge of a roof and having windows or louvers for lighting or ventilating a building, as a factory or warehouse.

11. an articulated mounting for a nozzle, usually mechanically operated, which permits a stream of water to be played in any desired direction, as in firefighting or hydraulic mining.

12. Also called giant.  (in hydraulic mining) a nozzle for dislodging and breaking up placer deposits with a jet of water.

13. any of various large lizards of the family Varanidae, of Africa, southern Asia, the East Indies, and Australia, fabled to give warning of the presence of crocodiles: several species are endangered.

---

verb (used with object)

• monitors,
  present (3rd person singular)
• monitored,
  past participle,  past
• monitoring
  present participle

1. Radio and Television.

   1. to listen to (transmitted signals) on a receiving set in order to check the quality of the transmission.

   2. to view or listen to (television or radio transmissions) in order to check the quality of the video or audio.

   3. to listen to (a radio conversation or channel); keep tuned to.

2. to observe, record, or detect (an operation or condition) with instruments that have no effect upon the operation or condition.

3. to oversee, supervise, or regulate.

   to monitor the administering of a test.

4. to watch closely for purposes of control, surveillance, etc.; keep track of; check continually.

   to monitor one's eating habits.

verb (used without object)

• monitors,
  present (3rd person singular)
• monitored,
  past participle,  past
• monitoring
  present participle

1. to serve as a monitor, detector, supervisor, etc.

monitor British  

/ ˈmɒnɪtə /

noun

1. a person or piece of equipment that warns, checks, controls, or keeps a continuous record of something

2. education

   1. a senior pupil with various supervisory duties

   2. a pupil assisting a teacher in classroom organization, etc

3. a television screen used to display certain kinds of information in a television studio, airport, etc

4. the unit in a desk computer that contains the screen

5. 1. a loudspeaker used in a recording studio control room to determine quality or balance

   2. a loudspeaker used on stage to enable musicians to hear themselves

6. a device for controlling the direction of a water jet in fire fighting

7. any large predatory lizard of the genus Varanus and family Varanidae, inhabiting warm regions of Africa, Asia, and Australia See also Komodo dragon

8. Also called: giant.  mining a nozzle for directing a high-pressure jet of water at the material to be excavated

9. (formerly) a small heavily armoured shallow-draught warship used for coastal assault

---

verb

1. to act as a monitor of

2. to observe or record (the activity or performance) of (an engine or other device)

3. to check (the technical quality of) (a radio or television broadcast)

monitor Scientific  

/ mŏn′ĭ-tər /

1. A device that accepts video signals from a computer and displays information on a screen. Monitors generally employ cathode-ray tubes or flat-panel displays to project the image.

2. See Note at pixel

---

Other Word Forms

Derived Forms

• monitorship
  noun
• monitress
  noun
• monitorial
  adjective
• self-monitoring
  adjective
• unmonitored
  adjective
• monitorially
  adverb

Inflected Forms

Nouns

• monitors
  plural

Participles

• monitoring
  present
• monitored
  past

Conjugated Forms

Present

• monitor
  simple
• monitors
  simple
• have monitored
  perfect
• has monitored
  perfect
• am monitoring
  progressive
• are monitoring
  progressive
• is monitoring
  progressive
• have been monitoring
  perfect progressive
• has been monitoring
  perfect progressive

Past

• monitored
  simple
• had monitored
  perfect
• was monitoring
  progressive
• were monitoring
  progressive
• had been monitoring
  perfect progressive

Future

• will monitor
  simple
• will have monitored
  perfect
• will be monitoring
  progressive
• will have been monitoring
  perfect progressive

Etymology

Origin of monitor

First recorded in 1540–50; from Latin: “prompter, adviser,” equivalent to monit(us) “reminded” (past participle of monēre) + -or -or

Explanation

A monitor is a device or a person who watches or checks to see that all is going well. If you're babysitting, you might use a baby monitor so you can hear if the baby cries in its sleep. Monitor can be used as a noun or a verb, both of which are concerned with watching over someone or something. A heart monitor displays the rhythm of your heart. A hall monitor is a person who checks to see that students aren't wandering the halls. If you are monitoring your grades, you are keeping track of them to see if they go up or down. And some parents buy a program that will monitor your Internet use, though you might think that this is an invasion of privacy.

Example Sentences

See Examples For:

monitor monitors monitored monitoring

“In my view, we were using improperly calibrated, sometimes faulty, and fundamentally insensitive equipment to monitor areas with known chemical hazards,” Dixon said.

From The Wall Street Journal ● Sep. 23, 2026

Detecting those jumps has been difficult, so the ability to monitor them in sound could provide an important new tool for identifying and correcting quantum errors.

From Science Daily ● Sep. 22, 2026

As this unprecedented El Niño approaches its likely peak towards the end of 2026, scientists will continue to monitor its development - and its impact on weather around the world.

From BBC ● Sep. 22, 2026

The merged company will have an oversight board that will monitor adherence to editorial independence from its owners and shareholders.

From Los Angeles Times ● Sep. 22, 2026

Besides keeping people farther away from harm, a big advantage of this is the ability to monitor a greater number of places.

From "Mountain of Fire" by Rebecca E. F. Barone

Four actors, affixed with in-ear monitors, occupy different seats as testimony is elicited, provided and undermined.

From Los Angeles Times ● Sep. 18, 2026

“CMS closely monitors the implementation of all models, including system performance and denial patterns, and is actively addressing issues as they arise,” CMS said in a statement to MarketWatch.

From MarketWatch ● Sep. 15, 2026

Working within the international system coordinated by UNESCO, it monitors earthquakes that could generate tsunamis and sends initial messages to French emergency authorities and other warning centers.

From Science Daily ● Sep. 10, 2026

The agency also monitors cases of diarrhoea brought on by reduced access to clean water due to the drought, with 225 cases so far this month.

From Barron's ● Sep. 8, 2026

It was like looking at monitors in one of those big security rooms: There was the third floor stairwell.

From "Shadowshaper" by Daniel José Older

They monitored the trees throughout the day in near natural greenhouse conditions while varying the amount of water available.

From Science Daily ● Sep. 23, 2026

She had done everything we asked: monitored her daughter’s progress, saved the report cards, trusted the school.

From The Wall Street Journal ● Sep. 23, 2026

With that thought in mind, the list below contains those value stocks currently recommended for purchase by at least two of the investment newsletters monitored by my performance-auditing firm.

From MarketWatch ● Sep. 17, 2026

"Groundwater tells a similar story: nearly two-thirds of monitored wells worldwide showed conditions outside the historical norm in 2025," Saulo said.

From Barron's ● Sep. 17, 2026

The lockout software also monitored my dietary intake.

From "Ready Player One: A Novel" by Ernest Cline

Their work is a sign of the times in the Premier League, with clubs across the top flight and beyond increasingly using data for transfers and monitoring their teams' performance.

From BBC ● Sep. 24, 2026

The agreement, once finalised, also includes a maintenance package, meaning Rolls-Royce will continue servicing and monitoring the engines throughout their operational life, officials said.

From BBC ● Sep. 24, 2026

Across several cities, effective schools shared strong leadership, high expectations, order, a clear academic mission and frequent monitoring of student progress.

From The Wall Street Journal ● Sep. 23, 2026

For now, the results highlight the importance of continued satellite monitoring of Arctic sea ice, along with the energy balance that controls how the ice melts and reforms.

From Science Daily ● Sep. 23, 2026

His idea was to offer the Russians a two-year moratorium on nuclear testing, with compliance to be verified by eight to twelve monitoring stations on each country’s territory.

From "Big Science" by Michael Hiltzik

Related Words

• audit
• check
• control
• follow
• keep an eye on
• observe
• oversee
• scan
• supervise
• survey
• track