text: whats the meaning of the saying "so long" and why does saying 'so long' translate to that meaning?   this is just a guess on my part, like many phrases in english, we often don't know their origins. but here is a stab at it. it could be short for "let's hope it won't be so long, until we meet again." or something of that ilk. it's obviously a farewell term. so that may fit.