The start of the first hour of the day on the 24-hour clock, i.e. 0:00, military time.

(military) The location of the center of a burst of a nuclear weapon at the instant of detonation. The zero point may be in the air, or on or beneath the surface of land or water, depending upon the type of burst, and it is thus to be distinguished from ground zero.

(military) A technique in which the first motion of the missile or aircraft removes it from the launcher. Normally, such a launch occurs before the missile fuel or aircraft engine is fired.

(physics) associated with zero on any scale, but particularly with a temperature of absolute zero

A vehicle that produces only carbon dioxide and water as its emissions and so does not pollute the air.

The state of apparent weightlessness which occurs in a very low gravity field, or in free fall.

(surveying) An optimal network design within a computer. It involves choosing an optimal reference system and revolving it around a certain real number.

plural of zero-point energy

(logic) Describing situations in which the veracity of a statement may be shown to be true without revealing any other information.

(cryptography) An interactive method for one party to prove to another that a (usually mathematical) statement is true, without revealing anything other than the veracity of the statement.