You are watching: How many years are in a semicentennial
Wikipedia says "Quadranscentennial", however I can"t find extensive use of that.
http://en.wikipedia.org/wiki/Anniversary
Is there any type of word because that what I"m feather for?

A 25th anniversary is a silver jubilee or silver anniversary, and also a celebration of that milestone would certainly be a Silver Jubilee.
The equivalent 50th anniversary is a golden jubilee, ~ which intake varies; as soon as celebrating personal achievements it is a diamond jubilee in ~ 60 and also platinum in ~ 70, as in the reign of a monarch, yet the 75th anniversary of the establishing of the young Scouts that America, for example, was a diamond jubilee.
If you desire to note a duration of time rather than the milestone, climate quarter century would carry out the trick and also simply speak 25th anniversary or 25 years.

Note the comment entry because that quadranscentennial together a term for 25th anniversary in the Wikipedia link:
Probably a modern-day coined term
Probably correct, in my opinion.
There space a few usages of quadranscentennial together a 25th anniversary occasion e.g. The Bhutan Quadranscentennial the Apollo 11 commemorative stamp issued in 1994. Yet I am uncertain if that was a transcription or spelling error, together I could not find any type of confirmation native an main Bhutan website.
For wedding commemoration, or regency, a hatchet in current use is "Silver Anniversary". Or "Silver Jubilee" in the instance of regents. That isn"t a Latin-ate term. But it is a typically understood term.

As friend pointed out, quadranscentennial is the technical term and also it is not extensively used. I have seen either:25th Anniversary orEvery 25 years
Depending on even if it is you"re talking around a one-time event (like a wedding anniversary) or a repeating occasion (none involved mind).

A duration of 25 year is a "Generation". The time from birth to someone having a kid of their own and beginning the next generation.

If semicentennial (semi-, precisely half, + centennial, a period of 100 years) is 50 years, climate quarticentennial (quart-, a combine form meaning "a fourth," + centennial) is effectively the -ennial word definition 25 years (and arguably much more correct 보다 quadrancentennial, since there is no combining kind of quadrant).
If you desire to coin words shot Latin-smashville247.net viginti-quinque-ennial. Latin viginti is twenty, quinque five.
I favor the indigenous “quarticentennial” said by Ellie Kesselman above. Like the words decennial, every 10 years, and also bicentennial, it’s a constant pairing through the “-centennial “ or “-cennial” root and Latin prefixes.
However, a centennial is an event, celebrated at 100 years. Words through the “-cennial” root, favor decennial, refer to a repeating cycle, e.g. Every 10 years.
However, in the heart of brevity, because that a native describing the cycle of every 25 years, what around “quarcennial”? “Quarti-“ just stumbles when spoken. ~ all, us say “Quarter-horse”, not “Quarti-horse”. “Quartercennial” is perhaps most correct, every quarter-century.
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Similarly, in the spirit of simplicity, albeit not word length, “quarter-centennial” come describe an event celebrated at 25 years is perhaps best of all, i m sorry was, ns think, the original question.