群发 qúnfā to mass send Origin Definitions Defs Strokes Stroke Words Sentences Sents 群发性地震 qúnfāxìngdìzhèn earthquake swarm a series of many small earthquakes occurring in a localized area over a short period of time群发性头痛 qúnfāxìngtóutòng cluster headache a severe headache that occurs in groups or cycles