root of thread

航海及海运专业英语词汇(R5) ... root of the contract 合同根基 root of thread 螺纹牙底 root of tooth 齿根 ...

直角三角形_馆档网 ... "接合根(熔接)"," root of joint" "螺纹根"," root of thread" "齿根"," root of tooth" ...