Beatlemania is a term that originated during the 1960s to describe the intense fan frenzy directed toward The Beatles during the early years of their success. The word is a portmanteau of "Beatle" and "mania", similar to the much earlier term Lisztomania used to describe fan reaction to the concerts of pianist Franz Liszt.
Andi Lothian, a former Scottish music promoter, claims that he coined the term while speaking to a reporter at the Caird Hall Beatles concert that took place as part of The Beatles' Mini-Tour of Scotland, on 7 October 1963, and an early printed use of the word is in The Daily Mirror 15 October 1963 in a news story about the previous day's Beatles concert in Cheltenham.
Beatlemania became common in the United States after The Beatles performed on The Ed Sullivan Show in 1964. It was characterised by intense levels of hysteria demonstrated by fans both at the actual concerts and during the band's travels to and from hotels, concert venues, and the like. (via)