Relating to or serving as a foundation; foundational (archaic or rare variant).
From 'foundation' + the suffix '-ary,' creating an alternative to 'foundational.' This variant appeared in 19th-century texts but was largely superseded by 'foundational,' which became the standard form.
The suffix '-ary' (found in 'library,' 'dictionary,' 'revolutionary') produces adjectives, but when 'foundationary' competed with the newer 'foundational,' language users chose the newer form—showing how English naturally eliminates redundant variants.
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