15-letter words containing t, o, l, s, y
- wolf-rayet star — a very hot (35,000–100,000 K) and luminous star in the early stages of evolution, with broad emission lines in its spectrum.
- yellow goatfish — a schooling goatfish, Mulloidichthys martinicus, inhabiting the Atlantic Ocean from Florida to Panama.
- yosemite valley — a glacial valley in Yosemite National Park in central California, in the Sierra Nevada Mountains. It has an altitude of about 1200 m (4000 ft), with sheer walls rising about another 1200 m (4000 ft).
- zoophysiologist — an expert in zoophysiology