Correct spelling for the English word "othelcosia" is [ˌɒθɪlkˈə͡ʊzi͡ə], [ˌɒθɪlkˈəʊziə], [ˌɒ_θ_ɪ_l_k_ˈəʊ_z_iə] (IPA phonetic alphabet).
1. Ulceration of the auricle of the ear or the auditory meatus. 2. Suppuration of the middle ear.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.