pith
名词 pith:
soft spongelike central cylinder of the stems of most flowering plants
the choicest or most essential or most vital part of some idea or experience
同义词:kernel, substance, core, center, essence, gist, heart, heart and soul, inwardness, marrow, meat, nub, sum, nitty-gritty
动词 pith:
remove the pith from (a plant)