the face of a timepiece; graduated to show the hours | a device for showing the operating condition of some system |
a disc on a telephone that is rotated a fixed distance for each number called | a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time |
the circular graduated indicator on various measuring instruments | a signal for attracting attention |
the control on a radio or television set that is used for tuning | (chemistry) a substance that changes color to indicate the presence of some ion or substance; can be used to indicate the completion of a chemical reaction or (in medicine) to test for a particular reaction |