Skottår is the Swedish term for a 'leap year', or a year with 366 days as opposed to the usual 365.
We have the skottår because the time it takes for the earth to complete its full journey around the sun is around 365.24 days, so without a leap year the calendar and seasons would gradually become out of sync with the seasons.
February 29th, the extra date added to the calendar, is called skottdag (Leap Year Day).
If you're wondering why the extra day was added to February and not simply at the end of the year, it's to do with Roman superstitions.
Their new year began on March 1st, and they added an extra, short month within the month we now call February. In the Gregorian calendar, which Sweden uses, the practice of extending the year at this point stuck.
Until 1996, February 24th was considered as the 'extra day' in both Sweden and Finland, until Leap Day was standardised across the EU as February 29th.
The skottdag was earlier considered an unlucky day in Sweden, and as in other countries, it was also seen as a bit of a 'topsy-turvy day' where traditions could be turned on their heads. For example, there was a tradition of skottårsbaler or Leap Year Balls where single women invited men.
And what about the word itself?
År means 'year' and comes from the Old Norse word ár. It's related to the English word 'year', but the difference is due to how different vowel sounds developed over the centuries in different parts of northern Europe.
Ett skott is most often used to mean 'a shot', including a shot fired on a weapon, a shot in sports (for example, a shot at the goal) or a camera shot.
It can also mean 'a shoot' in the botanical sense; the part of a plant or flower that includes the stem and the start of leaves or flowers.
But in the word skottår, skott means something different. It comes from the phrase skjuta in, which means 'to add in' or 'to insert'.
So while the English language term focuses on the fact that each date after February 29th leaps forward by two weekdays instead of one compared to the previous year, the Swedish language focuses on the individual extra day that has been pushed into the calendar.
I år är det skottår
This year is a leap year
Varför har vi skottår egentligen?
Why do we have leap years anyway? (a question you'll now be able to answer!)