equipment that involves the controlled conduction of electrons (especially in a gas or vacuum or semiconductor) | any of various large tropical carnivorous lizards of Africa and Asia and Australia; fabled to warn of crocodiles |
| a piece of electronic equipment that keeps track of the operation of a system continuously and warns of trouble |
| electronic equipment that is used to check the quality or content of electronic transmissions |
| display produced by a device that takes signals and displays them on a television screen or a computer monitor |
| someone who gives a warning so that a mistake can be avoided |
| someone who supervises (an examination) |