progradationWiktionary 原文英美构词拆解propro-前缀gradationgradation词干pro-agreeing with; supporting; favouring · substituting for词源说明Formed as pro- + gradation, after prograde.释义名词noun1(geology) The growth of a river delta farther out into the sea over time, as it gains more sediment同族词派生词 1progradational