sesquicentenarian UK /ˌsɛs.kwɪˌsɛn.təˈnɛəɹi.ən/US /ˌsɛs.kwɪˌsɛn.təˈnɛɹi.ən/ noun1 •(rare) Someone or something of 150 years of age, or between 150 and 159 (in its sixteenth decade of life or existence) formssesquicentenarians
