A variant or archaic form of 'elaborate'; to work out or develop something in detail.
This appears to be either a variant spelling or a back-formation from 'elaborated.' It's extremely rare in modern English and primarily appears in historical texts.
This word is so obscure that it barely appears in modern dictionaries—it's one of those linguistic ghosts that shows up occasionally in old texts, reminding us that spelling and word forms used to be much more fluid.
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