monitor

ot noun

1. Someone who watches over something; a person in charge of something or someone. The camp monitors look after the children during the night, when the teachers are asleep.
2. A device similar to a television set used as to give a graphical display of the output from a computer. The information flashed up on the monitor.
3. A program for viewing and editing. a machine code monitor
4. A device that detects and informs on the presence, quantity, etc., of something.

fe’l verb

1. To watch over; to guard.