柯林斯詞典conchoid /?k??k??d/ 1. N a plane curve consisting of two branches situated about a line to which they are asymptotic, so that a line from a fixed point (the pole) intersecting both branches is of constant length between asymptote and either branch. Equation: (x – a)2(x2 + y2) = b2x2 where a is the distance between the pole and a vertical asymptote and b is the length of the constant segment 蚌線[geometry] 返回 conchoid