leading

leading The distance between two lines of text in a document. Increasing the leading increases the line spacing and generally improves readability. In most word-processing and desktop-publishing applications, the leading is measured from the baseline of one line to the baseline of the next line. So if one has 10 point text with a 12 point leading, the distance from baseline to baseline is 12 points. This meaning is different from that in traditional printing usage, where the leading was the extra space between lines. So, in the example above, the leading would be 2 points (12 points would be the body size and the type would be described as “10 on 12pt” or “10pt with 2pt leading”). The term comes from the old printing technique of using metal (lead) type to increase the line spacing by placing thin strips of lead between the rows of type.