Origin of term Good-Bye

Seems a very straight-forward term, rolls easily off the tongue. Very convenient. But the term has a bigger meaning. It is derived from the ancient wish: God be with you. Seems feasible, right ? Well, read on:

Sometimes we are so familiar with a word that we forget what we are saying. We might imagine that good-bye might be related to bye-ways and bye-laws but that is not the case. The good of good-bye is identical to the good of Good Friday. That it is, it is not "good" at all but "God". Good-bye is a shortened form of "God be with ye/you" which dates from Shakespeare's time. Godspeed, a 15th century way of saying "good-bye", comes from God speed, meaning "may God prosper one".

"In the Spanish adios and French adieu 'farewell, good-bye', we see an explicit wish that the person addressed should be in the care of God (dios, dieu). The same sentiment lies at the origin of good-bye, which comes from the phrase God be with you. The phrase gradually eroded over time, appearing in such versions as God be wy you (in the sixteenth century), God b'y you (in the seventeenth), and numerous other versions before settling on good-bye in the nineteenth century, the final form buttressed by the example of good night and good day. In time good-bye was further shortened simply to bye, at which point reduction could scarcely proceed further. To some speakers, indeed, this meager monosyllable seemed in need of fattening, so they produced the reduplicaton bye-bye.