otacousticon
/ˌəʊtəˈkuːstɪkɒn/Now historical and rare
noun
An instrument to assist hearing, such as an ear trumpet.
Origin
Early 17th century; earliest use found in Thomas Tomkis (b. c1580), playwright. From ancient Greek ὠτ-, οὖς ear + ἀκουστικόν, neuter of ἀκουστικός acoustic. Compare ancient Greek ὠτακουστής.