Holy week is one entire week.
holy friday
The days that Holy Week occurs during the week before Easter. Also known as the final week of lent, it begins on Palm Sunday and lasts through Holy Saturday.
Roman Catholic AnswerOur Blessed Lord, after being in the tomb for three days, rose from the dead.
There is no specific day of the week. Instead, the holy days or "days of rest" are connected to the lunar cycle. Which I believe are full, new and the two halfs meaning that there are still four days a month but are not connected to week days.
Fasting for 3 days.
One week is 233 and 1/3rd percent of three days.
There are more than three Jewish holy days, but the answer you're looking for is Rosh Hashanah and Yom Kippur, which total three days. For more about these and the rest of the Jewish holy days and other occasions, see this linked page.
.Roman Catholic AnswerThe three most Holy Days of the year are usually considered Easter, Pentecost, and Christmas.
The Easter Triduum
This sounds like a job description. It means you will work three days out of the week to start with.
Sunday, Christmas, & Easter.