Where does “foundationary” come from?

foundationary (English) comes from English ary, from English e'er, from English ever, from Middle English ever, from Old English ǣfre.

Ancestry of “foundationary”, step by step

foundationary traces back through two separate lines of ancestry.

via English ary

StepLanguageWordMeaning
1Englisharyany
2Englishe'erContraction of ever
3EnglisheverAlways, frequently, forever; Continuously,...
4Middle Englisheverever
5Old Englishǣfre

via English foundation

StepLanguageWordMeaning
1EnglishfoundationThe act of founding, fixing, establishing, or...
2Middle Englishfoundacioun
Every word from Old English ǣfre