ful·gide \-ˌjīd, -_jə̇d\noun (-s) Etymology: German fulgid, from fulg- (from Latin fulgēre) + -id -ide 1.: the anhydride C6H4O3 of fulgenic acid 2.: a derivative of fulgenic acid (as some aryl derivatives used in photography to produce removable light images in blue and black tones)