"FF/SH aconto i året" is an example of a really bad sentence construct in Danish. It means either "PTO/Holidays accrued this year" or "PTO/Holidays paid this year". Aconto means "on account", but doesn't make sense in this context, and "i året" is "this year" or "current year", but should arguably have been "dette år" or "indeværende år", so the correct sentence should have read "FF/SH udbetalt indeværende år" or "FF/SH opsparet indeværende år".

Now for the definitions:

FF is the abbreviation for Feriefridag, or PTO (Vacation as a subset of PTO) in English (US). It is different from vacation in Danish law as you vacation is accrued (on average) a year in advance, whereas FF are days that you can use as soon as they have been accrued, and gives the employee a chance to have days off that are not governed by the Danish Vacation Law, and can be used without length advance notices. They were introduced in 1999 (1 day), and increased by 1 day per year thereafter (2 days in 2000, 3 days in 2001).

SH is Søgnehelligdag, which is one of 4 major Danish groupings/types of days: Hverdag (Weekday), Lørdag (Saturday), Søndag (Sundays) and Søgnehelligdag (Holidays).

The word Søgnehelligdag is a construct of 2 words Søgne and Helligdag, which means a holiday defined by the church (holidays in Denmark are only defined by the church, i.e. our Constitution Day on 5th of June, Christmas Day, and New Years Day may be company holidays, but not holidays according to the rules on Søgnehelligdag).

Here comes the kicker: A Weekday or a Saturday can be converted into Søgnehelligdag, but a Sunday can NEVER be anything but a Sunday. Why is this important? Because union agreements for some groups of workers defines more pay on a Søgnehelligdag, and that does not kick in for Sunday. So, if e.g. Boxing Day falls on a Sunday, too bad!

Got a little longer than necessary, sorry about that...