n. & v.
--n. (pl. -os)
1. a the figure 0; nought. b no quantity or number; nil.
2 a point on the scale of an instrument from which a positive or negative quantity is reckoned.
3 (attrib.) having a value of zero; no, not any (zero population growth).
4 (in full zero-hour) a the hour at which a planned, esp. military, operation is timed to begin. b a crucial moment.
5 the lowest point; a nullity or nonentity.
--v.tr. (-oes, -oed)
1. adjust (an instrument etc.) to zero point.
2 set the sights of (a gun) for firing.
Phrases and idioms:
zero in on 1 take aim at.
2 focus one's attention on. zero option a disarmament proposal for the total removal of certain types of weapons on both sides. zero-rated on which no value added tax is charged. zero-sum (of a game, political situation, etc.) in which whatever is gained by one side is lost by the other so that the net change is always zero.
Etymology: F z{eacute}ro or It. zero f. OSp. f. Arab. sifr CIPHER