so long

Noun so long has 1 sense

• so long(n = noun.communication) adieu, adios, arrivederci, au revoir, auf wiedersehen, bye, bye-bye, cheerio, good day, good-by, good-bye, goodby, goodbye, sayonara - a farewell remark; "they said their good-byes"
is a kind of farewell, word of farewell