1. tercentenary - Noun
2. tercentenary - Adjective
Including, or relating to, an interval of three hundred years.
The three hundredth anniversary of any event; also, a celebration of such an anniversary.
Source: Webster's dictionaryForrest and Greaves 1982: xi The tercentenary of Bunyan's birth, celebrated in 1928, elicited praise from his former adversary, the Church of England. Source: Internet
Essays to celebrate the tercentenary of the birth of Lord Burlington. Source: Internet
The play commemorated the tercentenary of Shakespeare's death. Source: Internet