fill color: Also called shading, the color or pattern that fills the background of one or more cells.

firewall: Keeps other people or programs from accessing your computer without your permission.

font: A standard way of making each letter. (It’s also called a typeface.)

font size: Controls the height of the letters. The font size is based on the distance from the top of the tallest letter to the bottom of the lowest letter, measured in points.

formula: A math expression that begins with an equals sign, such as =2+1. Formulas can also contain cell references. For example, =A2+B2 adds the amount found in cell A2 to the amount found in B2.

function: In Excel, a function refers to a certain math calculation.