AINU Meaning of AINU in English [ 'eɪnu: ]■ noun ( plural same or ~s ) 1》 a member of an aboriginal people of northern Japan. 2》 the language of the ~, perhaps related to Altaic.Originthe name in ~, lit. 'man, person'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004