/
ˈzɪərəʊ/
cardinal number
 (pl. zeros)
 the figure 0; nought; nothing. 
▸a point on a scale or instrument from which a positive or negative quantity is reckoned.
 ▸a temperature of 0°C (32°F), marking the freezing point of water.
 ▸the lowest possible amount or level; nothing at all.
 ▸informal a worthless or insignificant person.
v.
 (zeroes, zeroing, zeroed)
  - adjust (an instrument) to zero.
- set the sights of (a gun) for firing. ▸
(zero in on)
 take aim at or focus attention on. 
Etymology
C17: from Fr. zéro or Ital. zero, via Old Sp. from Arab. ṣifr ‘cipher’.