[ adj ] of or relating to or completing a period of 300 years <adj.pert>
Planners of Peoria's tricentennial celebration are going shopping across the river for a little history.
William and Mary is planning to celebrate next year not the tricentennial of its charter (which will take place in six years) but the "Glorious Revolution" of 1688 that put William III and Mary II on the throne of England.