rheostat

The story

1. Proto-Indo-European*ser-?
2. Proto-Indo-European*srew-
3. Proto-Indo-European*sréweti
4. Proto-Hellenic*hréwō
5. Ancient Greekῥέω (rhéō)
6. Englishrheo-
7. English todayrheostat

From rheo- (prefix meaning ‘current; flow’) + -stat (suffix forming the names of scientific instruments which render the prefixed elements static or stationary in some respect), coined by the English physicist and inventor Charles Wheatstone (1802–1875) in an 1843 journal article: see the quotation. * Rheo- is derived from Ancient Greek ῥέω (rhéō, “to flow, stream”), ultimately from Proto-Indo-European *srew- (“to flow, stream”), possibly from *ser- (“to flow”). * -Stat is derived from Ancient Greek -στάτης (-státēs), from ῐ̔́στημῐ (hĭ́stēmĭ, “to stand; to stop”), ultimately from Proto-Indo-European *steh₂- (“to stand (up)”).

Words from the same roots

First known use, by meaning

• from 1843 An electrical resistor with two terminals, the resistance of which can be varied continuously by moving a knob or slider to regulate the flow of an electric current.
• from 1843 Such a device used to regulate the brightness of an electric light; a dimmer.