A five-year period is a period of five years.
A five-year period is a temporary period of five years . The term comes from the Latin word lustrum and is linked to the lustratio , a ceremony that took place every five years in Ancient Rome and Ancient Greece .
The lustratio implied a purification . In the case of the Romans, divine protection was sought to be guaranteed through various rituals that allowed the herds, lands and even the army to be purified. Attendance at the event was mandatory for all citizens. For the Greeks, lustratio made it possible to reverse the disgrace that weighed on a city or person.
With the advancement of history , the lustratio ceased to exist, although its periodicity ended up giving rise to the concept of lustrum. Thus, today any period that extends for half a decade is mentioned in this way.
How long does a five-year period last?
A five-year period, therefore, is equivalent to sixty months . Its beginning may or may not coincide with the beginning of a year : the important thing is that the stage extends over five years.
Suppose the government of a nation decides to build a new hospital. The works begin in March 2013 and end in March 2018 ; that is, five years later. It can be stated, in this way, that the construction of the health center took five years.
Take the case of a famous actor who lived outside his country between 1980 and 1985 . When reviewing his life in an interview, he comments that he lived abroad for five years, referring to the five years he spent away from his homeland.
Due to leap years, the length of the five-year period is not always the same.
A not so precise period
It is important to note that the five-year concept can be used with a certain degree of imprecision if the exact duration of an event is not so relevant. In other words, not every time we hear this term in a sentence it is translated as exactly five years, with each and every one of its days.
A possible explanation for this concession is that the years of our calendar (that is, in the Gregorian) do not always last the same: let us not forget that the leap year, the one that occurs every four years, has one day longer than the rest. This correction is carried out to compensate for the gap between the tropical year and the calendar.
Here we enter even more technical terrain. The time necessary for the average length of the Sun to increase by 360 in the ecliptic, that is, for it to complete one revolution, is called a tropical year or tropic year . This lasts 365.242189 days if calculated in mean solar time. The calendar year, on the other hand, simply lasts 365 days, and this generates the aforementioned lag .
Taking all this into account, we could say that a five-year period should always include four years of 365 days and one of 366, since in the Gregorian calendar there are no five-year periods that do not include a leap year . However, in everyday speech and even in areas of a certain level of precision, it is common for this concept to be used to describe a period that begins and ends in the same month, with a distance of approximately five years.
Other groups from years beyond five years
There are other terms that serve to express groups of years, and that are complementary to five years. To talk about two, ten, one hundred and one thousand years we can use biennium, decade, century and millennium , respectively.
Once again, it is not common for them to be used strictly, but we usually round the number of months and days. Additionally, a biennium can consist of two years of 365 days, but can also include a leap year. In the case of a decade, there should always be two leaps.