1. relating to or marking a 300th anniversary

1. a 300th anniversary or its celebration

Examples

• The university held a tercentennial celebration to mark its founding 300 years ago.
• The tercentennial committee planned events throughout the year.
• This tercentennial edition of the book includes historical essays.
• The city's tercentennial falls next year.
• They commissioned a special monument for the tercentennial.
• The tercentennial festivities attracted visitors from around the world.