Origin of the word Permittivity Who coined the word "permittivity"? It appears that first usage was in 1887. Please cite your source. 
 A: Oliver Heaviside "On the Self Inductance of Wires" Philosophical Magazine Series 5, volume 24, issue 146, 1887, page 79.
A: No it was known well before 1887.  Faraday was looking for a word to indicate a material through which an electrical field would penetrate.  He asked William Whewell - a polymath at Cambridge (UK), who suggested dielectric (considering dia-electric a bit clumsy): "As to the name for the antithetical classes of bodies, I consider thus. I suppose you called one class dimagnetic from analogy with dielectric. I think you ought to have said diamagnetic; for the bodies through (dia) which electricity goes would have been called diaelectric, but that vowels in such cases coalesce. I think you may keep diamagnetic for this class, and give to the opposite class a name implying that they rank along with magnetic bodies. I propose paramagnetic. (Whewell's emphasis)"
See:
J. Daintith (1994). Biographical Encyclopedia of Scientists. CRC Press. p. 943. ISBN 0-7503-0287-9.
Jump up ^ James, Frank A.J.L., editor. The Correspondence of Michael Faraday, Volume 3, 1841–1848, "Letter 1798, William Whewell to Faraday, p. 442.". The Institution of Electrical Engineers, London, United Kingdom, 1996. ISBN 0-86341-250-5
