indicator

nouns

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 signal for attracting attention
is derived from
is a type of (narrower)
any nonverbal action or gesture that encodes a message
"signals from the boat suddenly stopped"
a device for showing the operating condition of some system
is a type of (narrower)
an instrumentality invented for a particular purpose
"the device is small enough to wear on your wrist"; "a device intended to conserve water"
(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
domain category
the science of matter; the branch of the natural sciences dealing with the composition of substances and their properties and reactions
is a type of (narrower)
any material used for its color
"she used a different color for the trim"