zero (Noun) — A mathematical element that when added to another number yields the same number.
zero (Noun) — No amount at all; something of no value or importance.
zero (Noun) — The point on a scale from which positive or negative numerical quantities can be measured.
zero (Noun) — The sight setting that will cause a projectile to hit the centre of the target with no wind blowing.
zero (Adjective) — Indicating the absence of any or all units under consideration. ex. "a zero score"
zero (Adjective) — Having no measurable or otherwise determinable value. ex. "the goal is zero population growth"
zero (Adjective) — Indicating an initial point or origin.
zero (Adjective) — Of or relating to the null set (a set with no members).
zero (Verb) — Adjust (an instrument or device) to zero value.
zero (Verb) — Adjust (as by firing under test conditions) the zero of (a gun). ex. "He zeroed in his rifle at 200 yards"