Apeirogon

The Regular Polygon essentially equivalent to the Circle having an infinite number of sides and denoted with Schläfli Symbol $\{\infty\}$.

See also Circle, Regular Polygon

References

Coxeter, H. S. M. Regular Polytopes, 3rd ed. New York: Dover, 1973.

Schwartzman, S. The Words of Mathematics: An Etymological Dictionary of Mathematical Terms Used in English. Washington, DC: Math. Assoc. Amer., 1994.