monitor noun
1 television/computer screen
ADJ. colour | CCTV, computer, television/TV, video
PREP. on a/the ~ The security staff can see all the outside of the building on their CCTV monitors.
2 machine that records/checks sth
ADJ. foetal, heart, oxygen, pulse, radiation
MONITOR + VERB detect sth | show sth The heart monitor shows the strength of your pulse.
3 sb who checks sth is done fairly/properly
ADJ. EU, UN UN monitors declared the referendum fair. | school | health, peace