ONLINE
ETYMOLOGY DICTIONARY:
- rare metallic element, 1861, Modern Latin, from Gk. thallos "young shoot, green branch" (see thallus) + element name ending -ium. So called by its discoverer, Sir William Crookes (1832-1919), from the green line in its spectrum by which he detected it.
- Latin, from Gk. thallos "green shoot, twig," related to thalia "abundance," thalos "scion, child," ultimately from PIE root *dhal- "to bloom" (cf. O.Ir. duilesc, a type of algae).
WIKIPEDIA
- Thallium is a chemical element with symbol Tl and atomic number 81. This soft gray poor metal is not found free in nature.