Definitions:

1. A starting or reference point in a scale or system of measurement. NOUN
   • The thermometer was calibrated to zero point before testing.
2. In military and explosives context, refers to the exact location where a bomb or explosion is detonated. NOUN
   • Ground zero is the zero point of the blast.
3. In Physics, refers to the thoretical lowest possible temperature, where all molecular motion stops. NOUN
   • Scientists study particle behavior near the zero point of temperature.
4. In surveying, mapping, and navigation, relates to a reference location or coordinate. NOUN
   • The map's zero point was set at the equator and prime meridian.

Synonyms:

• ground zero
• null point
• origin
• zero