monitor

(noun) someone who supervises (an examination). Synonyms: proctor.

(noun) someone who gives a warning so that a mistake can be avoided. Synonyms: admonisher, reminder.

(noun) an ironclad vessel built by Federal forces to do battle with the Merrimac. Synonyms: Monitor.

(noun) display produced by a device that takes signals and displays them on a television screen or a computer monitor. Synonyms: monitoring device.

(noun) electronic equipment that is used to check the quality or content of electronic transmissions.

(noun) a piece of electronic equipment that keeps track of the operation of a system continuously and warns of trouble.

(noun) any of various large tropical carnivorous lizards of Africa and Asia and Australia; fabled to warn of crocodiles. Synonyms: monitor lizard, varan.

(verb) keep tabs on; keep an eye on; keep under surveillance. Synonyms: supervise. Examples: "We are monitoring the air quality." "The police monitor the suspect's moves."

(verb) check, track, or observe by means of a receiver.