16-letter words containing o, n, e, i, r
- zero-zero option — (in international nuclear arms negotiations) an offer to remove all intermediate-range nuclear missiles, if the other side will do the same
- zollner illusion — a spatial illusion in which parallel lines intersected by short oblique lines are perceived as converging or diverging.
- zone of interior — the part of a theater of war not included in the theater of operations.