Meaning of sesquicentennial

ses•qui•cen•ten•ni•al

Pronunciation: (ses"kwi-sen-ten'ē-ul), [key]
— adj.
  1. pertaining to or marking the completion of a period of 150 years.
—n.
  1. a 150th anniversary or its celebration.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.
See also:
sesquicarbonate sesquioxide