val·e·dic·to·ri·an /-ˌdɪkˈtoriən, ˈtɔr-/
  致告別辭者
  Val·e·dic·to·ri·an n. One who pronounces a valedictory address; especially, in American colleges, the student who pronounces the valedictory of the graduating class at the annual commencement, usually the student who ranks first in scholarship.
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  valedictorian
       n : the student with the best grades who delivers the
           valedictory at graduation [syn: valedictory speaker]