Name Box at the top left above the sheet. Used to display cell references and to give and display cell names. Formula bar shows the contents of a selected cell, whether it is plain text, numbers, or a calculation formula. Sometimes the whole bar containing the Name Box and the formula text box is called the Formula bar. Sometimes just the formula text box is meant.
Most formulas use cell references to get the values to calculate with.
This is the cell that receives your keystrokes and commands. You make a cell the active cell when you select it, by clicking it or by moving into it with keys. The TAB or the arrow keys are handy for moving from cell to cell. What you typed is now contained in the cell. You select a range by dragging, for example from the upper left cell to the lower right cell.