from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A slender, usually tubular body of glassy rock produced by lightning striking and then fusing dry sandy soil.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. glass formed by a lightning strike melting sand or other material
from the GNU version of the Collaborative International Dictionary of English
- n. 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.
from The Century Dictionary and Cyclopedia
- n. A tube formed, usually in loose sand, but sometimes in the solid rock, by lightning; a lightning-tube.
- n. An explosive of the nitroglycerin class, used for blasting: similar to dynamite, but the nature of the dope has not been disclosed by the inventor.
Latin fulgur, lightning; see fulgurate + -ite1.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Latin fulgur. (Wiktionary)