indicator

Pronunciation

• IPA: UK /ˈɪn.dɪ.keɪ.tə/, US /ˈɪn.dɪ.keɪ.t̬ɚ/^[1]

Etymology

It is borrowed from Late Latin indicātor, an agent noun from Latin indicō (“to point out, show”) (see indicate).^[2][3]

Earliest recorded meaning

That which indicates or suggests something: 1666 in the OED and Merriam-Webster, the 1660s in Etymonline.^[4][3][2]

Semantic evolution

The muscle that extends the forefinger is the indicator from 1696.^[4][2] A steam cylinder's pressure gauge is from 1839,^[2] and in chemistry a substance that shows the state of a solution from 1842–3.^[4] In geology an indicator was a clue to the presence of gold (1894), and in ecology a group of species whose presence signals particular conditions (1906).^[4] A device on a vehicle signalling a turn is from 1932.^[2] In Northumberland and Durham mines an indicator showed the brakesman where the cage was in the shaft.^[5]

Timeline

• 1666 – that which indicates.^[4][3]
• 1696 – the forefinger muscle.^[4]
• 1839 – a pressure gauge.^[2]
• 1842–3 – an indicator (chemistry).^[4]
• 1932 – a vehicle's indicator.^[2]

Modern meaning

Noun

1. Something that indicates something, especially a trend: economic indicators.
2. A pointer, gauge or meter showing the condition of a machine or system.
3. (chemistry) A substance that shows by its colour the state of a solution, such as whether it is acid or alkaline.
4. (British) A flashing light on a vehicle signalling that it is about to turn.
5. (ecology) A species whose presence indicates particular conditions.

Word family

• indicatory
• acid-base indicator
• airspeed indicator
• bank-and-turn indicator
• coincident indicator
• rate-of-climb indicator
• turn-and-bank indicator

Related words

• index
• indicate
• indication
• indicative
• indict

References

1. ^ Jones, Daniel (2011), Cambridge English Pronouncing Dictionary, 18th ed., ed. Peter Roach, Jane Setter and John Esling, Cambridge: Cambridge University Press
2. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
3. ^ a b c Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ a b c d e f g Simpson, J. A.; Weiner, E. S. C., eds. (1989), The Oxford English Dictionary, 2nd ed., Oxford: Clarendon Press
5. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)