INDICATOR

noun Date: 1666 one that indicates: as, an index hand (as on a dial) ; pointer , b. gauge 2b, dial 4a, an instrument for automatically making a diagram that indicates the pressure in and volume of the working fluid of an engine throughout the cycle, 2. a substance (as litmus) used to show visually (as by change of color) the condition of a solution with respect to the presence of a particular material (as a free acid or alkali), tracer 4b, an organism or ecological community so strictly associated with particular environmental conditions that its presence is indicative of the existence of these conditions, any of a group of statistical values (as level of employment) that taken together give an indication of the health of the economy, ~y adjective