"adios" in the noun sense
1. adieu, adios, arrivederci, auf wiedersehen, au revoir, bye, bye-bye, cheerio, good-by, goodby, good-bye, goodbye, good day, sayonara, so long
a farewell remark
"they said their good-byes"
Source: WordNet® (An amazing lexical database of English)
Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.
View WordNet® License