OtsuJapanese O means "big, great" and tsu means "harbor, seaport".
ŌtsuboJapanese From Japanese 大 (o) meaning "big, great" and 坪 (tsubo), a traditional unit of measurement equivalent to approximately 3.306 square metres.
RavenEnglish, Dutch From a variety of sources all ultimately derived from the name of the bird. Could be a patronymic form of a given name such as Raven, Hraban, or Walraven; from a nickname referring to dark hair or thieving tendencies; or from a toponym derived from a given name.
RavenscroftEnglish, English (British) Habitational name from a minor place in Cheshire, England. The place name means "Hræfn's croft", from an Old English personal name Hræfn (itself from Old English hræfn meaning "raven", possibly a byname) and Old English croft meaning "enclosed field".