—n. 1. the figure or symbol 0, which in the Arabic notation for numbers stands for the absence of quantity; cipher.
2. the origin of any kind of measurement; line or point from which all divisions of a scale, as a thermometer, are measured in either a positive or a negative direction.
3. a mathematical value intermediate between positive and negative values.
4. naught; nothing.
5. the lowest point or degree.
6. Ling.the absence of a linguistic element, as a phoneme or morpheme, in a position in which one previously existed or might by analogy be expected to exist, often represented by the symbol &zeroslash;: Inflectional endings were reduced to zero. The alternant of the plural morpheme in “sheep” is zero. 7. Ordn.a sight setting for both elevation and windage on any particular range causing a projectile to strike the center of the target on a normal day, under favorable light conditions, with no wind blowing.
8. Math. a. the identity element of a group in which the operation is addition.
b. (of a function, esp. of a function of a complex variable) a point at which a given function, usually a function of a complex variable, has the value zero; a root.
9. (cap.) a single-engine Japanese fighter plane used in World War II.
—v.t. 1. to adjust (an instrument or apparatus) to a zero point or to an arbitrary reading from which all other readings are to be measured.
2. to reduce to zero.
3. Slang.to kill (a congressional bill, appropriation, etc.): The proposed tax increase has been zeroed for the time being. 4. zero in,to aim (a rifle, etc.) at the precise center or range of a target.
5. zero in on, a. to aim directly at (a target).
b. to direct one's attention to; focus on; concentrate on.
c. to converge on; close in on.
—adj. 1. amounting to zero: a zero score. 2. having no measurable quantity or magnitude; not any: zero economic growth. 3. Ling.noting a hypothetical morphological element that is posited as existing by analogy with a regular pattern of inflection or derivation in a language, but is not represented by any sequence of phonological elements: the zero allomorph of “-ed” in “cut”; “Deer” has a zero plural. 4. Meteorol. a. (of an atmospheric ceiling) pertaining to or limiting vertical visibility to 50 ft. (15.2 m) or less.
b. of, pertaining to, or limiting horizontal visibility to 165 ft. (50.3 m) or less.
6. being or pertaining to the precise time, as a specific hour or second, when something must or does happen, as the explosion of a nuclear weapon: in an underground shelter at zero second.