There are mixture of terms for signifying time off other than your normal days off per week

Sat and Sun for Monday to Friday workers when they used to work 40 hour week used to be the rostered days off

Then the 38 hour week came along in the early 1980's and you got an Accrued Day Off per month, by working 40 hours being paid 38 and having 2 hours per week go to paid day off, which simply meant you had to accrue time from your working week over 38 to go towards your paid day off per month ADO.

Then you had flex time in the white collar public service sector, where you worked longer hours but weren't paid overtime for them and when you had enough you had day off

Somewhere along the way RDO became the common term for the ADO and your weekend was simply the weekend.