From the second edition (1989):
before a vowel ot-, a. Gr. ὠτο-, combining form of οὖς, ὠτ- ear, an element of medical and other scientific words, the more important of which appear in their alphabetical places.

otocaˈtarrh, catarrh of the ear (Mayne Expos. Lex. 1857). otoˈconia [F. otoconie (Breschet); Gr. κονία or κόνις dust], term for the white pulverulent dust found in the membranous labyrinth of the inner ear, the aggregation of which forms an otolith. (Sometimes treated as if pl. of otoconium; also in Eng. form otokonies.) Hence otoˈconial a.; oˈtoconite = otolith. ˈotocrane [Gr. κρανίον the skull], the auditory capsule, the portion of the petrous bone which encloses the organ of hearing; hence otoˈcranial, otoˈcranic adjs. ˈotocyst [F. otocyste (Lacaze Duthies), f. Gr. κύστις bladder], term for the auditory vesicle or organ of hearing in some of the Invertebrata; hence otoˈcystic a., of or connected with an otocyst. ‖otoˈdynia [Gr. ὀδύνη pain], ear-ache; hence otoˈdynic a. (Mayne). oˈtography [-graphy], description of the ear (Dunglison Med. Lex. 1842); hence otoˈgraphical a. otomorˈphology, the morphology of the ear. ‖otomyˈcosis [mycosis, Gr. µύκης fungus], the presence of parasitic fungi in the external auditory meatus. oˈtopathy [Gr. πάθος suffering], disease of the ear (Dunglison 1853); hence otoˈpathic a. ˈotophone [Gr. ϕωνή sound], an ear-trumpet, an apparatus for the conveying of sound to the deaf; also = otoscope 1. ˈotoplasty [Gr. πλάσσειν to mould], plastic surgery of the ear; hence otoˈplastic a. (Mayne). ‖ˌotopyˈosis [Gr. πύωσις formation of pus], suppuration in the ear. ‖otoˈrrhœa [Gr. ῥοία a flow], purulent discharge from the ear; hence otoˈrrhœal, otoˈrrhoic adjs., relating to otorrhœa. ‖otoˈsalpinx [Gr. σάλπιγξ war-trumpet], the Eustachian tube. oˈtosteal [Gr. ὀστέον bone] a., relating to the auditory ossicle; n., applied by Owen to the homologues of the bones of the inner ear, in fishes, etc. oˈtotomy [-tomy], dissection of the ear (Dunglison, 1843). otoˈtoxic a., having a toxic effect on the ear or its nerve supply; so ˌototoˈxicity, the property of being ototoxic.

1855 Holden Hum. Osteol. (1878) 278 The two masses are the ‘*otoconia’ or ‘otoliths’. 1881 Mivart Cat 301 Two sacs connected by a narrow bent tube and containing within them small crystals of carbonate of lime, called otoliths, or otoconia. 1842 E. Wilson Anat. Vade M. (ed. 2) 472 The membranous labyrinth‥contains two small calcareous masses called *otoconites. 1854 Owen Skel. & Teeth in Circ. Sc., Organ. Nat. I. 171 The organ of hearing,‥the surrounding vertebral elements being modified to form the cavity for its reception, which is called ‘*otocrane’. 1872 Mivart Elem. Anat. 138. 1857 Mayne Expos. Lex., *Otocranial, of or belonging to the otocrane. 1877 Huxley Anat. Inv. Anim. iv. 189 In some there is a sac filled with calcareous matter (*otocyst?) attached to the ganglion. 1878 Bell Gegenbaur's Comp. Anat. 533 The primitive otocyst is the foundation of a complicated cavitary system. 1880 E. Ray Lankester in Nature XXII. 147 The presence of velar *otocystic canals constitutes the chief peculiarity of the genus Craspedacusta. 1836–9 Todd Cycl. Anat. II. 567/2 *Otokonies‥found in the sacculus vestibuli of the ears of Cephalopods. 1900 Miss Ellis Human Ear 42 As otology is a medical term for the science of the ear, we should prefer to use the new word (suggested by Dr. R. Garnett) *otomorphology, the science of the shape of the ear. 1877 Burnett Ear 284 *Otomycosis is said to be much more frequently met among the poorer classes. 1839 D. J. Moriarty Husband Hunter II. 109 Perceiving the *otophone properly fixed. 1888 Amer. Ann. Deaf Jan. 85 Examination of 15 deaf persons in the Pennsylvania Inst. by means of Maloney's Otophone. 1818–20 Thompson tr. Cullen's Nosologia 302 Local Diseases‥Of the Secretions and Excretions‥*Otorrhœa. 1878 T. Bryant Pract. Surg. I. 89 Deafness is not unfrequent, the hearing failing without any external disease, such as otorrhœa. 1877 tr. von Ziemssen's Cycl. Med. XII. 808 *Otorrhœal abscess of the brain. 1857 Mayne Expos. Lex., *Otorrhoic. 1854 Owen Skel. & Teeth in Circ. Sc., Organ. Nat. I. 177 A body as hard as shell, like half a split almond‥it is the ‘*otosteal’‥or proper ear-bone. 1868 —— Anat. Vertebr. III. 246 The otosteals conduct vibrations from the tympanic membrane to the vestibular one. 1951 Trans. 10th Conf. Chemotherapy of Tuberculosis 224 The growing list of tuberculostatic antibiotics which have an *ototoxic action‥suggests that still other substances derived from Streptomyces may be expected to show a similar toxicity. 1967 Busch & Lane Chemotherapy v. 86/2 The ototoxic effect is exerted primarily on the cochlear division of the 8th nerve. 1974 Arch. Path. XCVI. 304/1 Methyl mercury is a unique ototoxic agent. 1951 Trans. 10th Conf. Chemotherapy of Tuberculosis 224 (heading) *Ototoxicity of hydroxystreptomycin. 1975 Nature 3 Jan. 45/1 Kanamycin ototoxicity yields such cochlear lesions that histological and audiometric measures are well correlated.