valedictory

adjective

1. bidding goodbye; saying farewell: a valedictory speech.
2. of or relating to an occasion of leave-taking: a valedictory ceremony.

noun, plural val·e·dic·to·ries.

3. an address or oration delivered at the commencement exercises of a college or school on behalf of the graduating class.
4. any farewell address or oration.

noun plural -ries

1. a farewell address or speech
2. US and Canadian a farewell speech delivered at a graduation ceremony, usually by the most outstanding graduate

adj.

1650s, from Latin valedictum (past participle of valedicere; see valediction) + -ory. Valedictory address is recorded from 1779.