isobront

Etymology
+ (see ).

Noun

 * 1)  An isoline drawn through geographical points at which a given phase of thunderstorm activity occurred simultaneously.
 * 2)  An isoline drawn through geographical points which, on average, experience the same number of thundery days per year.
 * 1)  An isoline drawn through geographical points which, on average, experience the same number of thundery days per year.