Batching from batch means for example:
a quantity or number coming at one time or taken together the quantity of material prepared or required for one operation to combine, mix, or process at once
I remember starting using it since I read The 4-Hour Workweek: Escape 9-5, Live Anywhere, and Join the New Rich. A simple example is laundry. You don’t wash only because one thing is dirty, you wait until you can fill the washing machine.
You can use it also for other parts in life. The most useful part for me is to answer all incoming social media messages in a batch. For me thats for example once in the morning (the exception is, if I have an appointment with someone then I use for example Whatsapp to only communicate with that person and ignore all the other messages). This saves a lot of time and keeps my mind free of thinking about what to answer.
There are other examples also, like exampled from Tim Ferris himself:
How Batching Can Help You Maximize Your Productivity | Tim Ferriss