IMPONDERABLES
Noun
imponderables
plural of imponderable
Source: Wiktionary
IMPONDERABLE
Im*pon"der*a*ble, a. Etym: [Pref. im- not + ponderable: cf. F.
impondérable.]
Definition: Not ponderable; without sensible or appreciable weight;
incapable of being weighed.
Im*pon"der*a*ble, n. (Physics)
Definition: An imponderable substance or body; specifically, in the plural,
a name formely applied to heat, light, electricity, and magnetism,
regarded as subtile flyids destitute of weight but in modern science
little used.
Source: Webster’s Unabridged Dictionary 1913 Edition