<p><strong>Noun</strong></p><ul><li>the figure or symbol 0, which in the Arabic notation for numbers stands for the absence of quantity; cipher.</li><li>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.</li><li>a mathematical value intermediate between positive and negative values.</li><li>naught; nothing.</li><li>the lowest point or degree.</li><li>Linguistics: 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 0̷.</li><li>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.</li><li>Mathematics: the identity element of a group in which the operation is addition.</li><li>a point at which a given function has the value zero; a root.</li><li>(initial capital letter) a single-engine Japanese fighter plane used in World War II.</li></ul><p><strong>Verb</strong></p><ul><li>to adjust (an instrument or apparatus) to a zero point or to an arbitrary reading from which all other readings are to be measured.</li><li>to reduce to zero.</li><li>Slang: to kill (a congressional bill, appropriation, etc.).</li></ul><p><strong>Adjective</strong></p><ul><li>amounting to zero: a zero score.</li><li>having no measurable quantity or magnitude; not any: zero economic growth.</li><li>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.</li><li>(of an atmospheric ceiling) pertaining to or limiting vertical visibility to 50 feet (15.2 meters) or less; relating to, or limiting horizontal visibility to 165 feet (50.3 meters) or less.</li><li>zero-coupon.</li><li>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.</li></ul><p><strong>Verb Phrase</strong></p><ul><li>to aim (a rifle, etc.) at the precise center or range of a target.</li><li>to direct one's attention to; focus on; concentrate on.</li><li>to converge on; close in on.</li></ul>