Weekends are easy to define: they come at the end of the week. However, there is a big difference between the end of a working week and the end of a week in retirement.
As a worker, the weekend was your lifeboat to sanity, a chance to do whatever it was that you wanted to do, or had to do - but had no time for during the week - as well as a chance to de-stress. As a retired person the weekend is just another two consecutive days.
Then again it isn’t. As a retired person, the weekend is what you used to celebrate in the past and that workers celebrate in the present. Those workers will be all around you and you will be aware of this.
Perhaps that is all that a weekend needs to mean to a retired person. It is what others celebrate around you. Meantime, you can set your own routine: one that doesn’t need to consider that any day of the week is special.
I have seen a church in Italy that has a painting of a skeleton above which is written. “I once was what you are and what I am you also will be”. Sounds like a description of a weekend in retirement.
Retirement: You won’t know what it is like until you get there.