Present participle of monitor, noun_ The act of listening, carrying out surveillance on, and/or recording the emissions of one's own or allied forces for the purpose of maintaining and improving procedural standards and security, or for reference, as applicable, the act of observing something (and sometimes keeping a record of it), The act of detecting the presence of signals, such as electromagnetic radiation, sound, or visual signals, and the measurement thereof with appropriate measuring instruments

the act of observing something (and sometimes keeping a record of it)