from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A line drawn through geographical points at which a given phase of thunderstorm activity occurred simultaneously.
from the GNU version of the Collaborative International Dictionary of English
- n. An imaginary line, or a line on a chart, marking the simultaneous development of a thunderstorm, as noted by observing the time when the thunder is heard at different places.
from The Century Dictionary and Cyclopedia
- n. A line on a map or chart connecting those places at which a given peal of thunder is heard simultaneously.
Sorry, no etymologies found.