accumulation point

accumulation point (plural accumulation points)

1. (topology) (said to be "of" a given subset of a topological space) a point whose every neighborhood contains infinitely many points belonging to the given subset
   • 1975, Bert Mendelson, Introduction to Topology, Third edition, New York: Dover Publications, Inc., published 1990, →ISBN, OCLC 932232056, §5.3, page 173:

     LEMMA 5.2    Let X be a Hausdorff space and A a subset of X. A point ${\displaystyle a\in X}$ is an accumulation point of A if and only if a is a limit point of A.

• isolated point

• limit point

• condensation point

• accumulation point on Wikipedia.Wikipedia