Xu Collection, Upper Volume Radical: Gate (mén) Threshold Kangxi stroke count: 16 Page 1337, Entry 17 Classical citations: Pronounced yu. Defined in Explanation of Script and Phrases (Shuowen jiezi) as the wooden board across a doorway. Mentioned in the Analects of Confucius (Lunyu): one should not step on the threshold when walking. Xu notes: it is a door sill. The Erya: Interpretation of Palaces (Erya) states that the term die refers to the threshold. The commentary explains: it refers to the horizontal piece of wood under a door that serves as a boundary between the inside and outside. In the Book of Rites (Liji): guests do not enter through the middle of the gate and do not step on the threshold. The commentary notes: it is the door sill. In the Zuo Tradition (Zuozhuan): women do not go out of the gate to welcome or see off guests, and when seeing brothers, they do not step over the threshold. In the History of the Former Han (Qianhan shu): one's thoughts do not exceed the threshold of the home. The commentary notes: it refers to the door sill. Additionally, pronounced xu. The meaning is the same.