- A derivative of fluorescein used as a fluorescent acid dye for cytoplasmic stains and counterstains in histology and in Romanovsky-type blood stains. [G. eos, dawn]- e. B the disodium salt of 4′,5′-dibromo-2′,7′-dinitrofluorescein. SYN: acid red 91, e. I bluish. [C.I. 45400]- e. I bluish SYN: e. B.- e. y, e. Y the disodium salt of 2′,4′,5′,7′-tetrabromofluorescein. SYN: acid red 87, e. yellowish. [C.I. 45380]- e. yellowish SYN: e. y.* * *eosinophil
* * *eo·sin 'ē-ə-sən also eo·sine -sən, -.sēn n1) a red fluorescent dye C20H8Br405 obtained by the action of bromine on fluorescein and used esp. in cosmetics and as a toner also its red to brown sodium or potassium salt used esp. as a biological stain for cytoplasmic structures2) any of several dyes related to eosin
* * *n.a red acidic dye, produced by the reaction of bromine and fluorescein, used to stain biological specimens for microscopical examination. Eosin may be used in conjunction with a contrasting blue alkaline dye taken up by different parts of the same specimen.
* * *eo·sin (eґo-sin) [Gr. ēōs dawn] any of a group of related pink to red acid dyes that are halogenated derivatives of fluorescein, including eosins B and Y and ethyl eosin, as well as other related compounds. When used specifically, the term usually denotes eosin Y.
Medical dictionary. 2011.