We sometimes call 50 years 5 decades, but half a centuryis more common.
It's called a Semicentennial. http://en.wikipedia.org/wiki/Anniversary
There is no dedicated word for a period of 50 years
Well, darling, a period of one year is called a "year." It's not rocket science, sweetie. Just like how a period of one month is called a "month." Keep it simple, honey.
A ten year period is a decade.
a 12 month period is called a fiscal year, there is also a natural year.
A period of six months is called half a year.
Yes until they reach menopause.
Or menopause.
a five-year period is a quinquennium
It's called a decade.
A period of 100 years is called a century.
The most expensive months are: June, July August, the rest of the year sort of in between.