Webster’s Revised Unabridged Dictionary · 1913
Tricentenary
Tri·cen′te·na·ry (·sĕn′tē·nā·ry̆), a. [Pref. tri- + centenary.] Including, or relating to, the interval of three hundred years; tercentenary. — n. A period of three centuries, or three hundred years, also, the three-hundredth anniversary of any event; a tercentenary.