monitor:

(plural: ‘monitors‘)

to monitor = to carefully watch or supervise something or somebody

class monitors keeping a class in the absence of the teacher

class monitors minding a class in the absence of the teacher

a person (or a device) that looks after, checks, controls or keeps track of someone or something as a job in a office, organisation, etc.;

a person whose job is to listen to foreign news on radio or watch foreign programmes on TV and report their contents to the state authorities;

a senior student with special responsibilities, such as keeping order, checking students conduct, helping junior students with simple needs, minding the class when the teacher is away, etc.;

a student who assists a teacher in a classroom or during some classroom activities other than the instruction classes,

e.g.

In the past when land-line telephones were maintained manually, there used to be senior operators called monitors to monitor/supervise the telephone operators in a telephone exchange.

Most teachers depend entirely on the help of their class monitors while on field trips.

Monitors in most schools wear special badges to show their position clearly.

For a sports news article that shows us how we come across this word in our daily browsing, please click here, for an article that explains the duties of a class monitor, please click here and for an article that gives tips on how to be a good class monitor, please click here.

Note 1: In American schools, there is a ‘school monitor’, an employee whose job is to monitor/supervise students behaviour and general conduct; a ‘hall monitor’ a student of a school whose duty is roam about the corridors and halls of the school building to maintain order during school hours; and a ‘bus monitor’ an employee whose job is to keep order and mind the safety of the students on school bus. For an article about the duties of a hall monitor, please click here & for an article that explains the duties of a bus monitor, please click here.
Note 2: ‘Monitor’ is more commonly used to refer to a device/tool that keeps continuous recordings of some activity, the screen that shows pictures on a TV set, a screen on a computer, for an article that explains what a computer monitor, please click here; and also as a verb, ‘to monitor’, to mean ‘to look over’, ‘to look after’, ‘to supervise’, etc. someone or something.