scintilla n.

Middle English shinen, from Old English scinan "shed, send forth, or give out light; be radiant, be resplendent, illuminate," of persons, "be conspicuous" (class I strong verb; past tense scan, past participle scinen). This is reconstructed to be from Proto-Germanic *skeinanan (source also of Old Saxon and Old High German skinan, Old Norse and Old Frisian skina, Dutch schijnen, German scheinen, Gothic skeinan "to shine, appear"), which perhaps is from a PIE root *skai- "to shine, to gleam" (source also of Old Church Slavonic sinati "to flash up, shine").

Of smoothed or polished surfaces, "gleam, give off reflected light," late Old English. Of a person, a face, "be fair-skinned, be beautiful," c. 1200. Also used in Middle English of night when cloudless and starlit. The transitive sense of "cause to shine" is from 1580s; the meaning "to black (boots)" is from 1610s. Related: Shined (in the shoe polish sense), otherwise shone; shining.

"sparkling, glittering, gleaming" as fixed stars do, c. 1600 in heraldry, from Latin scintillantem (nominative scintillans), present participle of scintillare "to sparkle, glitter, gleam, flash," from scintilla "spark" (see scintilla).