valediction
nounUK /ˌvæl.ɪˈdɪk.ʃən/
US /ˌvæl.əˈdɪk.ʃən/
A valediction is the words you say when you say goodbye to someone.
At the end of the school year, the principal gave a short valediction to the graduating class.
OTHER MEANINGS
2. The act of saying goodbye or the ceremony of parting.
The soldiers exchanged a quiet valediction before boarding the bus.
3. A speech or statement delivered at a farewell occasion, such as a graduation.
Her valediction at the ceremony moved everyone to tears.
4. Words used to close a letter or message.
He ended the note with the valediction 'Yours sincerely.'