sesquicentenary

 
Pronunciation: /ˌsɛskwɪsɛnˈtiːn(ə)ri, -ˈtɛn-/

noun (plural sesquicentenaries)

  • the one-hundred-and-fiftieth anniversary of a significant event: the year in which both celebrate their sesquicentenaries

adjective

  • relating to a sesquicentenary: part of the Society’s sesquicentenary celebrations