zero-zero

Short definition from Wiktionary

Adjective

1. 1
   Pertaining to the ejection of the occupant of an aircraft from a grounded stationary position (i.e. zero altitude and zero airspeed).
2. 2
   Pertaining to weather conditions of zero ceiling and zero visibility (i.e., opaque cloud all the way down to ground level), or to aircraft operations in such conditions.
3. 3
   Involving neither of two powers increasing their stockpile of nuclear weapons.