资料来源 : pyDict

双切; 双切线; 二重切

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Bitangent \Bi*tan"gent\, a. [Pref. bi- + tangent.] (Geom.)
   Possessing the property of touching at two points. -- n. A
   line that touches a curve in two points.