Word Study
class day
CIDE DICTIONARY
class day,
In American colleges and universities, a day of the commencement season on which the senior class celebrates the completion of its course by exercises conducted by the members, such as the reading of the class histories and poem, the delivery of the class oration, the planting of the class ivy, etc. [Webster 1913 Suppl.]
For further exploring for "class day" in Webster Dictionary Online