indicator

indicator /in·di·ca·tor/ (in´di-kat?er)

1. the index finger, or the extensor muscle of the index finger.

2. any substance that indicates the appearance or disappearance of a chemical by a color change or attainment of a certain pH.

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in·di·ca·tor (nd-ktr)

n.

1. One that indicates, especially a pointer or an index.

2. An instrument used to monitor the operation or condition of an engine, an electrical network, or another physical system; a meter or gauge.

3. The needle, dial, or other registering device on such an instrument.

4. Any of various substances, such as litmus or phenolphthalein, that indicate the presence, absence, or concentration of another substance or the degree of reaction between substances by means of a characteristic change, especially in color.

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indicator,

n a mark or symptom specific to a condition or disease.

indicator, biologic,

n a small quantity of harmless bacteria
(B. stearothermophilus) placed into an object prior to sterilization, the subsequent death of which indicates that sterilization has taken place. See B. stearothermophilus.

indicator chemical,

n a temperature-sensitive mark that changes color when a specific temperature has been reached. Used in the heat sterilization process but is by itself not proof that an object has been sterilized.

indicator diseases,

n opportunistic infectious diseases or neoplastic diseases that are associated with primary immunodeficiency disease, such as caused by the retrovirus HIV-1.

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indicator

1. a piece of information that suggests a suitable line of action, in diagnosis, treatment or control.

2. any substance that indicates the appearance or disappearance of a chemical by a color change or attainment of a certain pH.

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indicator plants

plants (e.g. Astragalus and Xylorrhiza spp.) that prefer a higher than normal soil content of a particular element, e.g. selenium, copper. Their presence indicates a potentially poisonous pasture. Called also obligate accumulator plants.