val·e·dic·to·ri·an
noun/ˌvælɪdɪkˈtɔːriən/
/ˌvælɪdɪkˈtɔːriən/
(North American English)- the student who has the highest grades in a particular group of students and who gives the valedictory speech at a graduation ceremony
（毕业典礼上）致告别辞的最优生 CultureMost schools also have a ‘salutatorian’, who has the next highest grades and gives the ‘salutatory’ speech (= speech of welcome to the event).