Word.ws English Dictionary

open sets

open sets is the plural of open set.

Meaning of open set

Noun

open set (plural open sets)

  1. Informally, a set such that the target point of a movement by a small amount in any direction from any point in the set is still in the set; exemplified by a full circle without its boundary.
  2. (restricted to metric spaces) A set which can be described as an (arbitrary) union of open balls. Equivalently, a set such that for every point in it, there is an open ball centered at that point, such that that open ball is contained by the set.
  3. Most generally, a member of the topology of a given topological space.

Questions about open sets

What is open sets the plural of?
Open sets is the plural of open set.

Words near open sets in the dictionary

  1. open secret
  2. open secrets
  3. open sesame
  4. open sesames
  5. open set
  6. open sets
  7. open shop
  8. open shops
  9. open slather
  10. open someone's eyes
  11. open sores

Source and license

Adapted from Wiktionary: open sets (page history and authors); open set (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

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Cite this entry: “open sets.” Word.ws, https://word.ws/open_sets. Based on Wiktionary, CC BY-SA 4.0.