Valediction
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.
For the greetings counterpart to valediction, see salutation.
Alternatively, valediction can refer to the final prayers and remarks at the graveside before burial given by the presiding priest, after the Mass and the rite of Final Commendation, during a Roman Catholic funeral service, or to a speech given by a valedictorian at a commencement.
English
Valedictions normally immediately precede the signature in written correspondence. The word or words used express respect, esteem, or regard for the person to whom the correspondence is directed, and the exact form used depends on a number of factors — including:
the formality of the correspondence
the relationship to the recipient
Conventions also change over time and differ according to language.