Definitions
from The Century Dictionary and Cyclopedia
 n. One of a pair of foci, real or imaginary, to a plane curve, so related to another pair that if a quadrilateral be drawn having the two foci of each pair at opposite angles, the opposite sides will meet at the circular points at infinity, and consequently be tangent to the curve.
 n. Given any system of coaxal circles, another system of coaxal circles may be constructed such that every circle of either system cuts orthogonally every circle of the other system. The limiting points of either system are the antipoints of the limiting points of the other system.
Etymologies
Sorry, no etymologies found.
Examples

It is not a propoint or antipoint, but I don't find it in Bruner's thinking and urge it should be there.
Wordnik is becoming a notforprofit! Read our announcement here.
Comments
Log in or sign up to get involved in the conversation. It's quick and easy.