16-letter words containing z, i, t, 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.
- ziegler catalyst — any of a group of catalysts, such as titanium trichloride (TiCl3) and aluminium alkyl (Al(CH3)3), that produce stereospecific polymers