I might have missed your point, tsuwm, but it seems to me that the word "millennium" fits the original description put up by Rubrick in his opening post.

M-W defines it as follows:

1 a : the thousand years mentioned in Revelation 20 during which holiness is to prevail and Christ is to reign on earth b : a period of great happiness or human perfection
2 a : a period of 1000 years b : a 1000th anniversary or its celebration


What appears to be happening currently is that "commercialism" has picked up on the word; it appears in all sorts of guises, and has become overworked, with the result that the original meaning has changed to suit the usage in the media.

I hear advertisements on radio and TV - lines like "toys for your millennium", and "a special millennium offer". "M&Ms - the official candy of the millennium". By whose authority, other than the advertisers?

I'm probably suffering from millennium overload!