(n.) A line which approaches nearer to some curve than assignable distance, but, though infinitely extended, would never meet it. Asymptotes may be straight lines or curves. A rectilinear asymptote may be conceived as a tangent to the curve at an infinite distance.

approach bottleneck collision course concentralization concentration concourse concurrence confluence conflux congress convergence converging crossing focalization focus funnel hub meeting mutual approach narrowing gap radius spokes tangent