What does Greenwich Mean Time (GMT) mean??

Answer 1

GMT is a mathematical mean, defined in terms of the solar second, measured at the former location of the Royal Observatory in England, located on the Prime Meridian (zero degrees longitude). GMT is useful for navigation (when converted to UT1, which is outside the scope of this document), but not for time-keeping programs.
When speaking loosely, GMT and Coordinated Universal Time (UTC) are roughly the same, but careful speakers will note that GMT is based on the solar second, while UTC is based on the standard second. The delta between the two time systems is too small for humans to notice, but very important for computer programs and universal synchronization.

Answer 2

Greenwich is a district of London, England. The Prime Meridian (which is considered the central longitude line of the earth [0 degrees either east or west]) runs through Greenwich. The British Empire used to be the most powerful and largest empire in the world, so they naturally made themselves the center of all the maps.

The time zones of the earth are roughly based on longitudinal lines. In general, the time zones change every 15 degrees of longitude. Greenwich Mean Time is the time in Greenwich, London, England...the supposed longitudinal center of the world.

Answer 3

"Greenwich Mean Time" (GMT) is a term originally referring to mean solar time at the Royal Greenwich Observatory in Greenwich in London.

For more details, see the link below...

Answer 4

the standard time in the city of Greenwich , England. All time is + or - from that point.

Answer 5

it's the timezone that goes through the greenwich observatory in the UK.

Answer 6

24 hour mode.

Answer 7

http://en.wikipedia.org/wiki/Greenwich_Mean_Time

this will explain it better