myotisPronunciation: /mʌɪˈəʊtɪs/Definition of myotis noun an insectivorous bat with a slender muzzle and with the flight membrane extending between the hind legs and the tip of the tail. Genus Myotis, family Vespertilionidae: numerous species Origin:modern Latin, based on Greek mus, mu- 'mouse'myotis in other Oxford dictionaries Definition of myotis in the US English dictionary