n.
A planar cubic curve that is symmetric about the y-axis and that approaches the x-axis as an asymptote. Its equation is x2y = 4a2(2a - y), where a is a constant.
[witch (translation of Italian avversiera, versiera, confused with versiera, curve, turning, from New Latin versōria, from Latin versus, turned, reversed, past participle of vertere, to turn; see verse1) + Maria Gaetana Agnesi (1718-1799), Italian mathematician.]
![[P]](http://cache.lexico.com/g/d/premium_mh.gif){kind=small}
