amazingly impressive; suggestive of the flashing of lightning; "the skater's dazzling virtuosic leaps"; "these great best canvases still look as astonishing and as invitingly new as they did...when...his fulgurant popularity was in full growth"- Janet Flanner; "adventures related...in a style both vivid and fulgurous"- Idwal Jones
(law) an explanation of the fundamental reasons (especially an explanation of the working of some device in terms of laws of nature); "the rationale for capital punishment"; "the principles of internal-combustion engines"