1. The numerical symbol 0; a cipher.
2. Mathematics.
   1. The identity element for addition.
   2. A cardinal number indicating the absence of any or all units under consideration.
   3. An ordinal number indicating an initial point or origin.
   4. An argument at which the value of a function vanishes.
3. The temperature indicated by the numeral 0 on a thermometer.
4. A sight setting that enables a firearm to shoot on target.
5. Informal. One having no influence or importance; a nonentity: a manager who was a total zero.
6. The lowest point: His prospects were approaching zero.
7. A zero-coupon bond.
8. Informal. Nothing; nil: Today I accomplished zero.

pho?bic  (fbk)
adj.
Of, relating to, arising from, or having a phobia.
n.
One who has a phobia.

pho?bi?a (fb-)
n.

1. A persistent, abnormal, and irrational fear of a specific thing or situation that compels one to avoid it, despite the awareness and reassurance that it is not dangerous.
2. A strong fear, dislike, or aversion.