torsion/ˈtɔ:ʃn; `tɔrʃən/ n[U]1 twisting, esp of one end of sth while the other end is held fixed 扭转（尤指一端固定而扭转另一端）.2 state of being twisted in a spiral 被旋转成的螺旋形.
牛津英汉双解词典