'Fulgurite' definitions:

Definition of 'Fulgurite'

From: GCIDE

Fulgurite \Ful"gu*rite\, n. [L. fulguritus, p. p. of fulgurire to strike with lightning, fr. fulgur lightning: cf. F. fulgurite.] A vitrified sand tube produced by the striking of lightning on sand; a lightning tube; also, the portion of rock surface fused by a lightning discharge. [1913 Webster]