Zulu time

1. also Universal Time formerly Greenwich Mean Time—a measure of time that conforms, within a close approximation, to the mean diurnal rotation of the Earth and serves as the basis of civil timekeeping.

2. more commonly, the time at 0° longitude (the meridian of Greenwich), expressed thus, 0950Z, meaning 9:50 A.M. at the meridian of Greenwich.

See the Introduction, Abbreviations and Pronunciation for further details.

Greenwich Mean Time. The current time at the Royal Observatory on the Prime Meridian in Greenwich England. Used as a time standard worldwide.

See Universal Time.