海底扩张 hǎidǐkuòzhāng seafloor spreading Origin Definitions Defs Strokes Stroke Words Sentences Sents 海底 hǎidǐ noun seabed the deep sea; the depths of the ocean; seabed; seafloor扩张 擴張 kuòzhāng verbnoun to expand; expansion to expand or enlarge, especially in terms of power, influence, or territory