quadricentenary

quad·ri·cen·ten·a·ry

Q0008250 (kwŏd′rĭ-sĕn-tĕn′ə-rē, -sĕn′tə-nĕr′ē)n. pl. quad·ri·cen·ten·a·ries A 400th anniversary or celebration.adj. Of or relating to a span of 400 years or to a 400th anniversary.
[From alteration of Latin quadringentī, quadrigentī, four hundred (on the model of such words as tercentenary); see kwetwer- in Indo-European roots.]