- Noun. A pointer or index that indicates something.
- Noun. A meter or gauge.
- Noun. The needle or dial on such a meter.
- Noun. (chemistry) Any of many substances, such as litmus, used to indicate the concentration of a substance, or the degree of a reaction.
- Noun. (ecology) A plant or animal whose presence is indicative of some specific environment.
- Noun. (economics) A measure, such as unemployment rate, which can be used to predict economic trends.
- Noun. (UK) A trafficator.