A spool or cylindrical device designed to hold thread or wire near the ear, possibly used in textile work or hearing aid manufacturing.
From 'ear' plus 'spool' (from Dutch 'spoel'). This is likely an occupational or technical term from textile manufacturing or medical device assembly, now quite obscure.
Many English words from specific trades have completely vanished—'earspool' might have been common in 1800s textile factories but died when those industries moved and workers scattered, taking their jargon with them.
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