1. continuous observation and measurement of a variable; to check constantly on a given condition or phenomenon, e.g. blood pressure or heart or respiration rate.
2. very large lizard, up to 10 feet long. Aquatic or terrestrial, carnivorous and carrion-eating. Members of the family Varanidae, e.g. Varanus griseus, the desert monitor.
To observe and evaluate a function of the body closely and constantly over a period of time for diagnostic purposes.