Справка LibreOffice 25.2
The WeekdayName function returns the weekday name of a specified day of the week.
        WeekdayName(Weekday as Integer [,Abbreviate as Boolean [,FirstDayofWeek as Integer]])
    String
Weekday: Value from 1 to 7, Monday to Sunday, whose Week Day Name need to be calculated.
Abbreviate: Optional. A Boolean value that indicates if the weekday name is to be abbreviated.
FirstDayofWeek: Optional. Specifies the first day of the week.
| Именованная константа | Значение | Описание | 
|---|---|---|
| vbUseSystemDayOfWeek | 0 | Use National Language Support (NLS) API setting | 
| vbSunday | 1 | Sunday (default) | 
| vbMonday | 2 | Понедельник | 
| vbTuesday | 3 | Вторник | 
| vbWednesday | 4 | Среда | 
| vbThursday | 5 | Четверг | 
| vbFriday | 6 | Пятница | 
| vbSaturday | 7 | Суббота | 
Нет
        REM  *****  BASIC  *****
        Option VBASupport 1
        Sub Example_WeekdayName
         Dim tgf as Integer
         tgf = 6
         print tgf &" "& WeekdayName(tgf,False,vbSunday)
        End Sub