/ˈzɪərəʊ/
cardinal number

• No quantity or number; nought; the figure 0.
  • example - figures from zero to nine
  • synonyms - nought, nothing, cipher, nil, 0

verb

1. Adjust (an instrument) to zero.
   • example - zero the counter when the tape has rewound
   • synonyms - return to nought, return to zero, adjust to zero point
2. Set the sights of (a gun) for firing.
   • example - the rifle had been zeroed at an elevation of 200

/zəʊn/
noun

1. An area or stretch of land having a particular characteristic, purpose, or use, or subject to particular restrictions.
   • example - a pedestrian zone
   • synonyms - area, sector, section, belt, region, territory, tract, stretch, expanse, district, quarter, precinct, locality, neighbourhood, province, land
2. An encircling band or stripe of distinctive colour, texture, or character.
   • example - ‘Palmate’ sclerites are situated in the dorsal zone of the animal"s body.
3. A belt or girdle worn round a person"s body.
   • synonyms - girdle, sash, strap, cummerbund, waistband, band, girth

verb

1. Divide into or assign to zones.
2. Encircle as or with a band or stripe.