(plural zeros; also zeroes)
Etymology: French or Italian; French zéro, from Italian zero, from Medieval Latin zephirum, from Arabic ṣifr
a. the arithmetical symbol 0 or Ø denoting the absence of all magnitude or quantity
b. additive identity; specifically the number between the set of all negative numbers and the set of all positive numbers
c. a value of an independent variable that makes a function equal to zero <+2 and -2 are zeros of f(x)=x2-4> 2. — see number table 3. a. (1) the point of departure in reckoning; specifically the point from which the graduation of a scale (as of a thermometer) begins (2) the temperature represented by the zero mark on a thermometer b. the setting or adjustment of the sights of a firearm that causes it to shoot to point of aim at a desired range 4. an insignificant person or thing ; nonentity 5. a. a state of total absence or neutrality b. the lowest point ; nadir 6. something arbitrarily or conveniently designated zero II. adjective Date: 1810 1. a. of, relating to, or being a zero b. having no magnitude or quantity ; not any <zero growth> <zero tolerance> c. (1) having no phonetic manifestation <the zero modification in the past tense of cut> (2) having no modified inflectional form <a zero plural> 2. a. of a cloud ceiling limiting vision to 50 feet (15 meters) or less b. of horizontal visibility limited to 165 feet (50.3 meters) or less III. verb Date: 1913 transitive verb 1. to determine or adjust the zero of (as a rifle) 2. a. to concentrate firepower on the exact range of — usually used with in b. to bring to bear on the exact range of a target — usually used with in intransitive verb 1. to adjust fire on a specific target — usually used with in 2. to close in on or focus attention on an objective — usually used with in <investigators are zeroing in on a suspect>
New Collegiate Dictionary. 2001.