Where does “regular open” come from?

regular open (English) comes from English regular, from Middle English reguler, from Middle French regulier, from French régulier, from Old French reguler, from Latin rēgulāris, from Latin rēgula, from Latin -ula — Derives agent nouns from verbs, denoting someone...

regular open (English): Being the interior of its closure

Definitions

  1. Being the interior of its closure

Ancestry of “regular open”, step by step

regular open traces back through two separate lines of ancestry.

via English regular

StepLanguageWordMeaning
1EnglishregularBound by religious rule; belonging to a monastic...
2Middle Englishreguler
3Middle Frenchregulier
4Frenchrégulierregular; dependable; legitimate
5Old Frenchregulerconforming to Chrisitan law
6Latinrēgulārisductile (able to be formed into a bar)
7Latinrēgularule, bar
8Latin-ularegō + API → rēgula; tegō + API → tēgula;...
9Proto-Indo-European-tlomAlternative form of *-trom
10Proto-Indo-European-tromForms nouns denoting a tool or instrument
11Proto-Indo-European-tḗrDerives agent nouns from verbs, denoting someone...

via English open

StepLanguageWordMeaning
1EnglishopenNot closed; Not physically drawn together,...
2Middle Englishopenopen
3Old Englishopenopen
4Proto-West Germanic*opanopen
5Proto-Germanicupanazopen
6Proto-Indo-Europeanupóunder, below
7Proto-Indo-Europeanh₃ewp-
Every word from Proto-Indo-European -tḗrEvery word from Latin -ulaEvery word from Latin rēgula
regular open — Etymology, Origin & Word History | Etymology Explorer