:salamext:
good·bye or
good-bye also good-by
[Alteration (influenced by good day) of God be with you.]
WORD HISTORY No doubt more than one reader has wondered exactly how
goodbye is derived from the phrase “God be with you.” To understand this, it is helpful to see earlier forms of the expression, such as
God be wy you, god b'w'y, godbwye, god buy' ye, and
good-b'wy. The first word of the expression is now
good and not
God, for
good replaced
God by analogy with such expressions as
good day, perhaps after people no longer had a clear idea of the original sense of the expression. A letter of 1573 written by Gabriel Harvey contains the first recorded use of
goodbye: “To requite your gallonde [gallon] of godbwyes,
I regive you a pottle of howdyes,” recalling another contraction that is still used.
http://www.answers.com/topic/goodbye
So i think they say it meant 'god be with you' and Allaah knows best. :)