a device for showing the operating condition of some system | a piece of information about circumstances that exist or events that have occurred |
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 | a concept whose truth can be proved |
a signal for attracting attention | a statement or assertion of verified information about something that is the case or has happened |
(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 | an event known to have happened or something known to have existed |