Webster's English Dictionary

zero

Cross references:
  1. number                
 
1. ze.ro \'ze--(.)ro-, 'zi(*)r-(.)o-\ n or zeros also zeroes [F or It; F 
   ze`ro, fr. It zero, fr. ML zephirum, fr. Ar z] pl sub-dot>ssub-dot>ifr 1a: 
   the numerical symbol 0 : CIPHER  1b: the number represented by the symbol 0 
   that leaves unchanged any number  to which it is added 1c: the number 
   between the set of all positive numbers and the set of all n egative 
   numbers 2a1: the point of departure in reckoning; specif : the point from w 
   hich the graduation of a scale (as of a thermometer) commences 2a2: the 
   temperature represented by the zero mark on a thermometer  2b: the setting 
   or adjustment of the rear sight of a firearm that causes it  to hit where 
   aimed 3: a person or thing with no importance or independent existence : 
   NON ENTITY 4a: a state of total absence or neutrality  4b: the lowest point 
   : NADIR  5: something arbitrarily or conveniently designated zero 
2. zero aj 1a: of, relating to, or being a zero  1b1: ABSENT, LACKING {the 
   ~ modification in the past o f cut} 1b2: having no modified inflectional 
   form {~ plural}  of a cloud ceiling  2a: limiting vision to 50 feet or less 
    of horizontal visibility  2b: limited to 165 feet or less 
3. zero vt 1: to determine or adjust the zero of (as a rifle)  2a: to 
   concentrate firepower on the exact range of - usu. used with i n 2b: to 
   bring to bear on the exact range of a target - usu. used with  in 1: to 
   adjust fire (as of artillery) on a specific target - usu. used wit h in 2: 
   to move near to or focus attention as if on a target : CLOSE m usu. used 
   with in