Names can be defined in Excel to store a fixed value or a formula. A cell or a range of cells can be given a name by: 

a. Selecting the range and keying in the name into the Name Box; or

b. Using the Insert Menu and choosing Name / Define.

Once the name is defined, it can be used in the sheet. In the screen shot below, the name is being used in a formula to find the weight of an object, given its mass.

Names can also contain formulae. In the name box below, the weight of the object is evaluated in the name weight using the stored values gravity and mass. This is useful when the result is required at multiple locations a worksheet.