Scintillation, n.
Etymology: [L. scintillatio: cf. F. scintillation.]
1. The act of scintillating.
2. A spark of flash emitted in scintillating. These scintillations are . . . the inflammable effluences discharged from the bodies collided. Sir T. Browne.
Shades of meaning
Fernald has no entry of its own for scintillation; he lists it under light.
Where he writes about it:
A sparkle is a sudden light, as of sparks thrown out; scintillation is the more exact and scientific term for the actual emission of sparks, also the figurative term for what suggests such emission; as, scintillations of wit or of genius. — from light