Names in Calc can contain letters, numeric characters, and some special characters. Names must start with a letter or an underline character.
Allowed special characters:
period (.) - allowed within a name, but not as first or last character
blank (?) - allowed within a name, but not as first or last character, and not for a cell range
Names must not be the same as cell references. For example, the name A1 is invalid because A1 is a cell reference to the top left cell.
Names must not start with the letters C or R followed by a number; also single characters C and R are not allowed as names. See the ADDRESS function for more information.
Names for cell ranges must not include blanks. Blanks are allowed within names for single cells, sheets and documents.
A good way of making the references to cells and cell ranges in formulas legible is to give the ranges names. For example, you can name the range A1:B2 Start. You can then write a formula such as "=SUM(Start)". Even after you insert or delete rows or columns, LibreOffice still correctly assigns the ranges identified by name. Range names must not contain any spaces.
For example, it is much easier to read a formula for sales tax if you can write "= Amount * Tax_rate" instead of "= A5 * B12". In this case, you would name cell A5 "Amount" and cell B12 "Tax_rate."
Use the Define Names dialog to define names for formulas or parts of formulas you need more often. In order to specify range names,
Select a cell or range of cells, then choose Sheet - Named Ranges and Expressions - Define. The Define Names dialog appears.
Type the name of the selected area in the Name field. Click Add. The newly defined name appears in the list below. Click OK to close the dialog.
You can also name other cell ranges in this dialog by entering the name in the field and then selecting the respective cells.
If you type the name in a formula, after the first few characters entered you will see the entire name as a tip.
Press the Enter key in order to accept the name from the tip.
If more than one name starts with the same characters, you can scroll forward through all the names using the CommandCtrl + Tab keys and backward using the Shift + CommandCtrl + Tab keys.