thionine

American  

[thahy-uh-neen, ‐nin] / ˈθaɪ əˌnin, ‐nɪn /

noun

Biochemistry.

1. a dark-green crystalline powder, C 12 H 10 N 3 S, whose property of turning violet in solution is useful in microscopy as a biological stain.

---

thionine British  

/ ˈθaɪənɪn, -ˌnaɪn, ˈθaɪəʊˌniːn /

noun

1. a crystalline derivative of thiazine used as a violet dye to stain microscope specimens

2. any of a class of related dyes

---

Etymology

Origin of thionine

First recorded in 1885–90; from Greek theîon “sulfur” ( see thio- ( def. )) + -ine ² ( def. )