An archaic or dialectal term, possibly referring to an arm or a type of limb or appendage in very old English usage.
From Old English 'earm,' which is an ancestor of the modern word 'arm,' related to proto-Germanic and Indo-European roots for limbs and appendages.
The word 'erme' is so archaic that it's barely attested in surviving texts—it's like finding a word that was already becoming obsolete in the Middle Ages, a linguistic ghost that reminds us how many words have silently vanished from English.
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