esp. UK, [esp. US] tercentennial [noun] [C] - the day or year which is 300 years after an important eventThis year is the tercentenary of the poet's birth.Tecentenary celebrations are being held next year to mark the founding of the college.
TERCENTENARY
Meaning of TERCENTENARY in English
Cambridge English vocab. Кембриджский английский словарь. 2012