He coined the term "Indo-European."
(1773 – 1829) An English polymath who made notable contributions to the many fields, including solid mechanics, linguistics, and Egyptology. In a work published in 1813, he coined the language term Indo-European.
1. In 1647 the Dutch linguist Marcus van Boxhorn — having noticed the same phenomenon — proposed the concept of what linguists came to call the Indo-European family of languages.
Quotation - "… Thomas Young was a polymath of epic proportions. When invited to contribute to the Encyclopaedia Britannica, he offered his expertise on the following headings: Alphabet, Annuities, Attraction, Capillary Action, Cohesion, Colour, Dew Egypt, Eye, Focus, Friction, Halo, Hieroglyphic, Hydraulics, Motion, Resistance, Ship, Sound, Strength, Tides, Waves and 'anything of a medical nature'.
Moreover, his knowledge of these subjects was not that of a mere dilettante: Young was a pioneering genius who had major impacts on any field that interested him."
(Source: Simon Singh in a review of The Last Man Who Knew Everything by Andrew Robinson)