1. an isolated point on a curve where the curve does not actually pass through the point but where the tangent lines meet
Usage: mathematics; geometry

Examples

• The equation x² + y² + 1 = 0 has an acnode at the origin.
• In algebraic geometry, an acnode represents a type of singular point.
• The curve has an acnode where it appears to touch itself but doesn’t actually intersect.
• Students often confuse an acnode with a node in their geometry studies.
• The mathematician identified the acnode by analyzing the curve’s derivatives.