>I note that "sesquicentennial" is considered an Americanism. Have our British cousins never celebrated the 150th anniversary of anything?

On a less flippant note. My school celebrated 150 years when I was there and I remember it was called the "150th Anniversary", no frills. I don't remember any clever words being used for any anniversaries. I don't even remember any "bicentennials" of anything British.

In general I like to celebrate everything .. Diwali, Hannukah, Christmas, whatever's going really, so why not coin a few words for anniversaries!