Scintilla

Existing in English since the seventeenth century

The Concise Oxford English Dictionary Edition

from Latin scintilla ("sparkling speck, atom").

Full definition of scintilla

(plural scintillae or scintillas)

1890, Philosophical Magazine, page 364,If the action of the electrodynamic waves is so violent that, even without artificial electrification of the secondary conductor, scintillÃ¦ occur in its spark-gap, the aluminium leaves remain almost without change.

1876 February, John Tyndall, , ,And, if I except the sagacious remark of General Duane which has been so curtly brushed aside, not a scintilla of light has been cast upon these causes by any researches ever published by the Lighthouse Board of Washington.
1878 April, John Tyndall, , ,Now, it may be we have no scintilla of proof to the contrary, but reason is unnecessary in reference to that belief which is of all the most settled, which nobody doubts or can doubt, and which he who should deny would stultify himself in so doing.
1990, William J. Brennan, Jr., , ,Current medical practice recommends use of heroic measures if there is a scintilla of a chance that the patient will recover, on the assumption that the measures will be discontinued should the patient improve.