[ 'zɪərəʊ ]
■ cardinal number ( plural ~s ) 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.
■ verb ( ~es , ~ing , ~ed )
1》 adjust (an instrument) to ~.
2》 set the sights of (a gun) for firing.
↘( ~ in on ) take aim at or focus attention on.
Origin
C17: from Fr. zéro or Ital. ~ , via Old Sp. from Arab. ṛifr 'cipher'.