Sesquicentennial originates from the Latin roots "sesqui-" meaning "one and a half" and "centennium" meaning "century," first used in the 19th century to denote a 150th anniversary.
Relating to the 150th anniversary of an event.
From Latin "sesquicentennialis," a compound of "sesqui-" (one and a half, from "semis" meaning half + "-que" meaning and) + "centum" (hundred, from PIE *ḱm̥tóm, hundred) + "-ennium" (from "annus," year, from PIE *h₂et-no-, year). The prefix "sesqui-" itself traces to PIE *semi- (half) + *-kʷe (and). The word denotes a 150th anniversary. First attested in American English in the mid-19th century when the United States
The prefix 'sesqui-' is used in various terms to denote a ratio of one and a half, and it is derived from the Latin word for 'one and a half'. The term 'sesquicentennial' is often used in the context of celebrations for institutions or events that have reached their 150th year.