What do we call the space between lines of text?

The space between lines of text is referred to as leading. This term originates from traditional typesetting, where strips of lead were used to create space between lines of type. Proper leading not only enhances readability but also ensures that the text has an aesthetically pleasing appearance.

Kerning, on the other hand, refers to the adjustment of space between individual letters to improve visual consistency and spacing. Line height is often used synonymously with leading in digital typography, but it primarily relates to the overall vertical spacing of text lines, which can include leading as well as additional spacing above or below the lines. Paragraph spacing refers to the space that is applied before or after a paragraph, distinct from the space between lines within that paragraph. Thus, leading is the correct term specifically for the space between lines of text.