Where does “Brethrenism” come from?

Brethrenism (English) comes from English ism, from English -ism, from Latin -ismus, from Ancient Greek -ισμός, from Ancient Greek -μός, from Proto-Indo-European -mós — Creates action/result nouns from verb stems.

Ancestry of “Brethrenism”, step by step

Brethrenism traces back through two separate lines of ancestry.

via English ism

StepLanguageWordMeaning
1EnglishismAn ideology, system of thought, or practice that...
2English-ismUsed to form nouns of action or process or result...
3Latin-ismus-ism
4Ancient Greek-ισμόςForms abstract nouns
5Ancient Greek-μόςForms abstract nouns
6Proto-Indo-European-mósCreates action/result nouns from verb stems

via English brethren

StepLanguageWordMeaning
1Englishbrethrenplural of brother; The body of members,...
2Middle Englishbrethren
3Old Englishbrōþorbrother
4Proto-West Germanicbrōþerbrother
5Proto-Germanicbrōþērbrother
6Proto-Indo-Europeanbʰréh₂tērbrother
Every word from Proto-Indo-European -mósEvery word from English -ismEvery word from English ism