cis|soid

cis|soid «SIHS oyd», noun, adjective. Geometry.

–n.

a curve originating at one end of the diameter of a circle which has a tangent to the circle at its opposite end, and so constructed that an oblique line from the point of origin intersecting consecutively the circle, the curve, and the tangent will always have equal segments representing the distance from the origin to the intersection with the curve, and the distance from the intersection with the circle to the tangent.

–adj.

contained between the concave sides of two curves which intersect each other.

╂[< Greek kissoeid like ivy < kissós ivy + eîdos form (from the curve's resemblance to angles on an ivy leaf)]