(n): a statement or assertion of verified information about something that is the case or has happened
(n): a signal for attracting attention
(n): any nonverbal action or gesture that encodes a message
(n): a device for showing the operating condition of some system
(n): an instrumentality invented for a particular purpose
(n): (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
(n): any material used for its color
