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.

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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, ˌmɒnɪˈtɔːrɪəl /

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

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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

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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 particular, we need to closely monitor how the situation in the Middle East could impact the real economy.”

From The Wall Street Journal ● Jul. 28, 2026

For some, though, this only strengthened their resolve to monitor agents to make sure they didn’t kill others.

From Slate ● Jul. 27, 2026

"Crews, specialist wildfire resources and partner agencies continue to monitor conditions closely and work to prevent further spread."

From BBC ● Jul. 24, 2026

A doctor can help manage side effects, monitor safety, and confirm that the medication is FDA-approved.

From Science Daily ● Jul. 24, 2026

“The behaviors we monitor include eating bamboo, locomotion, drinking, resting, sitting, exercise, investigating their surroundings, and scratching. The protocols are constantly being updated as the research progresses.”

From "Camp Panda" by Catherine Thimmesh

According to figures from the Amboseli Trust for Elephants, which monitors the movements of the animals, there were more than 2,000 elephants in the Amboseli ecosystem as of 2025.

From BBC ● Jul. 28, 2026

The civil war has seeded instability across Myanmar, creating fertile ground for organised crime groups running transnational scam operations to set up shop in fortified compounds, according to monitors.

From Barron's ● Jul. 28, 2026

So we stock up on air purifiers, now an $18 billion industry, along with indoor air quality monitors and subscription air filter services.

From Salon ● Jul. 19, 2026

A spokeswoman for Polymarket said the company monitors for potential insider trading and has made over 100 referrals to law enforcement.

From The Wall Street Journal ● Jul. 18, 2026

“Aye, C-c-captain,” Max stuttered from one of the cockpit monitors.

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

People with an increased risk of type 2 diabetes participated in a two-year lifestyle program and were then monitored for approximately nine years.

From Science Daily ● Jul. 28, 2026

A Bay Area resident stuck on a cruise ship with a deadly hantavirus outbreak has returned to Santa Clara County and is being monitored by health officials.

From Los Angeles Times ● Jul. 28, 2026

During the cruise, the magnetometer has continuously monitored the magnetic field carried by the solar wind.

From Science Daily ● Jul. 28, 2026

As a result, his minutes were carefully monitored throughout the tournament, with the forward starting only three of England's eight matches.

From BBC ● Jul. 19, 2026

The first stop was the south-east corner, where Foremole and his crew had a monotonous task: night and day they monitored the grounds for sounds of tunneling.

From "Redwall" by Brian Jacques

Most investors expect the Fed to hold rates at 3.50-3.75 percent for the fifth straight meeting, according to CME's FedWatch monitoring tool -- but bets on a rate-hike have been rising.

From Barron's ● Jul. 29, 2026

It also has applications in biomedical science, agriculture, environmental monitoring, and astrophysics.

From Science Daily ● Jul. 28, 2026

Much of the overtime money the department spent went instead toward preparing for unrest, monitoring protests and vigils, guarding hotels housing federal agents, and managing the public response to federal violence.

From Slate ● Jul. 27, 2026

The council said it was carrying out regular visual monitoring of the lake and arranging toxin testing, adding that warning signs will remain in place until the required safety criteria under the protocol is met.

From BBC ● Jul. 26, 2026

In the third year, I was made a prefect—a student who’s given some responsibility for monitoring the other kids and running some school activities—and I had my own room.

From "Facing the Lion" by Joseph Lemasolai Lekuton and Herman Viola

Related Words

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