quasquicentennial

[kwos-kwi-sen-ten-ee-uh l]
noun
  1. a 125th anniversary.
  2. a celebration marking such an anniversary.

Origin of quasquicentennial

quasqui- one and a quarter (pseudo-Latin, apparently qua(dri-) + (se)squi-) + centenial
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018