pith knot

pith knot [pɪθ nɔt]  [pɪθ nɑt] 

pith knot 基本解释
髓结;
pith knot 网络解释

1. 髓节:塑(性)变(形) plastic deformation | 髓节 pith knot | 弹性极限应力 stress of elasticity limit