otacousticn.adj.

1617 in J. Maidment Misc. Abbotsford Club (1837) 310 The nightbour phisicians applyed artificiall otacoustickis to his head and assured him that efter those preparatiounes the roaring of humane lyone wold dryue away all these noyces.

1646 H. Hammond View Exceptions to Visct. Falkland's Disc. Infallibilitie 79 Matters of fact, which we see or heare not with our own eyes or eares, but as with perspectives and otacoustickes.

1684 Philos. Trans. (Royal Soc.) 14 479 Otacousticks here come in for helping the ear.

1701 N. Grew Cosmol. Sacra i. v. §6 A Hare, which is very quick of hearing..is supplied with a Bony Tube; which, as a natural Otocoustick; is so directed backward, as to receive the smallest, and most distant Sound that comes behind her.

1740 J. Grassineau tr. S. De Brossard Musical Dict. 172 Otacoustics, is a term taken from the Greek, applied to instruments that add to, or increase the sense of hearing.

1803 T. Cavallo Elements Nat. or Exper. Philos. II. xi. 309 Most of the other terms which are used in treating of sound, are derived from the above-mentioned [Greek] words; such as diacoustics, viz. of refracted sound;..otacoustics, viz. of the means of improving the sense of hearing, as by means of the hearing trumpet, &c.

1889 New Eng. Med. Gaz. Nov. 506 The otacoustic can be worn on the top of the head, and so concealed by the hair that it cannot be detected.

1910 Official Gaz. (U.S. Patent Office) 8 Mar. 267/1 An otacoustic comprising an outer apertured shell, and an inner rotatable cup provided with a partition and an aperture at each side of said partition.

1653 H. Moseley in Ld. Brouncker tr. R. Descartes Excellent Compend. Musick To Rdr. sig. b^v The Artifice of Otocoustick Tubes, or Auriculary Meanders.

1747 B. Martin Philosophia Britannica II. vii. 72 Of otacoustic instruments.

1890 Hahnemannian Monthly July 447 She soon left this city,..taking with her an otophone with full instructions for the continuous daily application of otacoustic treatment.

2012 R. J. Ruben in T. R. Van De Water et al. Clin. Aspects Hearing ii. 6 Discovery of the motile properties of outer hair cells..and the probable associated sound production of the inner ear—otacoustic emissions—..has opened new areas for the investigation of basic and pathological aspects of the inner ear.

a1704 T. Brown Lett. from Dead to Living in Wks. (1707) II. 218 I undertook his Cure, and with a few of my Otacoustical Drops have so intirely recover'd him, that [etc.].

1893 Med. Fortn. 1 Mar. 143 Neither physical nor otacoustical phenomena alone are data invariably sufficient for infalliable diagnosis as to the nature of the aural morbid process underlying the impairment of hearing.

1906 E. Yellon Surdus in Search of his Hearing i. 25 To be efficient and of true benefit to the deaf person, an otacoustical instrument requires to be scientifically constructed.