Indicator may refer to:

In chemistry:

  • pH indicator, a chemical detector for protons in acid-base titrations
  • Redox indicator, a chemical detector for redox titrations
  • Complexometric indicator, a chemical detector for metal ions in complexometric titrations
  • Zeta potential, a property of interfaces in fluids for Zeta potential titration

In biology:

  • Indicator (genus), a genus of birds in the honeyguide family
  • Environmental indicator of environmental health (pressures, conditions and responses)
  • Ecological indicator of ecosystem health (ecological processes)

In economics:

  • Technical indicator, a tool used in the technical analysis of financial securities
  • Economic indicator or business performance indicator

In mathematics, engineering, and industry:

  • Indicator function of a subset of the domain, a concept in mathematics
  • Indicator (distance amplifying instrument), any of various instruments used to accurately measure small distances, and amplify them to make them more obvious
  • Indicator diagram, a graph of pressure against stroke within a piston engine

In society:

  • A synonym for the turn signal of an automobile