peneplainWiktionary 原文构词拆分pene-前缀Almost the thing or quality expressed by the root, as peneplain (almost a plain), peninsula (almost an island), penultimate (almost the last), penumbra (almost in shadow).+plain词根/词干词源说明From pene- + plain.释义（英文）名词 Noun(geomorphology) A low-relief plain representing the final stage of fluvial erosion during times of extended tectonic stability.