To reduce to cinders; to burn completely until only ash remains.
From the prefix 'en-' (to cause to be) plus 'cinder' (partially burned coal or wood). The word combines to mean 'to turn into cinders' and is a rare or archaic term.
When old books describe devastating fires that 'encindered' entire cities, it's a dramatic way of saying nothing was left but ash and blackened ruins—it's the kind of word you'd find in Victorian literature describing catastrophes like the Great Fire of London.
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