farewell:
A valediction (derivation from Latin vale dicere, 'to say farewell'), or complimentary close in American English, is an expression used to say farewell, especially a word or phrase used to end a letter or message, or the act of saying parting words- whether brief, or extensive.
http://en.wikipedia.org/wiki/Valediction
(In het vervolg kun je wellicht je vraag iets meer toelichten?)
