When you have an enormous spreadsheet, you don't always want to print the whole thing every time. You want to print just a chunk. Also, when you have an enormous spreadsheet, you don't want to have to re-specify, every single time, exactly which range you want to print.
So you define named ranges. One called Just Totals, maybe, one called January through March--whatever. Whatever the logical subchunks are that you want to print.
How do you easily A) define those ranges with a meaningful name and B) specify which ONE of those you want to print?
How to name a range
Select the range.
Choose Insert > Names > Define.
Name the range.
Now it shows up in this list. Any additional ranges you define will also show up here.
How to choose to print a range
So you're going along, minding your own business, somewhere else in the spreadsheet, and you decide you want to print a range.
Select the range name from the list.
The range is automatically selected.
Choose File > Print.
Select the Selected Cells item. Click Print. You'll only get the selected cells, aka only the ones in that named range.