世界地球日 shìjièdìqiúrì Earth Day Origin Definitions Defs Strokes Stroke Words Sentences Sents 世界 shìjiè noun world the whole earth or all countries; nature and human society as a whole地球日 dìqiúrì noun Earth Day An annual global event on April 22 to raise awareness for environmental protection; first observed in 1970 and later designated by the UN as International Mother Earth Day.