Synonym: center, core, essence, gist, heart, heart and soul, inwardness, kernel, marrow, meat, nitty-gritty, nub, substance, sum. Similar words: pithy, pithead, epithet, pithily, pit, pity, spit, spite. Meaning: [pɪθ] 
n. 1. soft spongelike central cylinder of the stems of most flowering plants 2. the choicest or most essential or most vital part of some idea or experience. v. remove the pith from (a plant).
n. 1. soft spongelike central cylinder of the stems of most flowering plants 2. the choicest or most essential or most vital part of some idea or experience. v. remove the pith from (a plant). 
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(61) The results showed: from pith outward, the tracheid length and diameter and cell wall thickness of Taxodium ascendens wood with or without intermittent flood all increased.
(62) Pith nucleus calcify can appear the symptom with lumbar inflexible activity, sure meeting reduces calcification the symptom that the dimension that vertebra provides causes a nerve root press press.
(63) Pith nucleus and model excise outside classics putamen " a way of escape " operation method is same, but pulling putamen to a side when, nerval of easy instead aggravating former horsetail is injured.