noun
: a part of space away from the earth assumed to have fixed coordinates so that the trajectory of an object (as a spacecraft or missile) may be calculated in relation to it
noun
: a part of space away from the earth assumed to have fixed coordinates so that the trajectory of an object (as a spacecraft or missile) may be calculated in relation to it
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012