EOSIN Meaning of EOSIN in English [ 'i:ə(ʊ)sɪn ]■ noun a red fluorescent dye that is a bromine derivative of fluorescein.OriginC19: from Gk ēōs 'dawn' + -in 1 . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004