regular open

adjective

Being the interior of its closure.

“The set (0,1)∪(1,2) is open, but is not regular open, because its closure is [0,2], so the interior of its closure is (0,2).”

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Meanings

adjectiveregular open (not comparable)
  1. not comparableraremathematicsBeing the interior of its closure.

    The set (0,1)∪(1,2) is open, but is not regular open, because its closure is [0,2], so the interior of its closure is (0,2).

Origin

From regular + open; apparently a backformation from regular open set.

Full word history & related roots →
Cite this entry
APA

regular open. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/regular%20open

MLA

“regular open.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/regular%20open. Accessed November 2, 2026.

Chicago

WatkinsX Dictionary, s.v. “regular open,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/regular%20open.

Source: regular open on Wiktionary, CC BY-SA 4.0.