16-letter words containing z, o, i, s
- zagros mountains — a mountain range in S Iran: has Iran's main oilfields in its W central foothills. Highest peak: Zard Kuh, 4548 m (14 920 ft)
- zenith telescope — a telescope mounted to point only at the zenith, used at some observatories for measuring time by the stars.
- zollner illusion — a spatial illusion in which parallel lines intersected by short oblique lines are perceived as converging or diverging.
- zygosporangium's — a sporangium that bears a zygospore.