Time GLOSSARY

Prime meridian: is the zero (0°) longitude, from which all other longitudes are measured. By international convention, it passes through the original site of the Royal Observatory in Greenwich, England; for this reason, it is sometimes called the Greenwich meridian.

Universal time: the international time standard common to every place in the world. Also known as world time.

Longitude: longitude is a series of imaginary lines on the earth's surface from the North Pole to South Pole. These lines of longitude are used to navigate and measure distance on Earth.

Greenwich Mean Time: GMT is the former name for mean solar time at the original site of the Royal Observatory in Greenwich, England. Also known as universal time.