In typesetting

Typesetting

Typesetting is the composition of text by means of types.Typesetting requires the prior process of designing a font and storing it in some manner...

, the term "interline spacing"

or "line leading"

refers to the space between consecutive lines of text, as between lines on a ruled sheet of paper. For example, text can be typeset with a font size of 11 pt and an interline spacing of 15 pt.

Interline spacing is often referred to as leading

Leading

In typography, leading refers to the distance between the baselines of successive lines of type. The term originated in the days of hand-typesetting, when thin strips of lead were inserted into the formes to increase the vertical distance between lines of type...

, a term that originated with hot-metal or cast-metal typesetting

Typesetting

Typesetting is the composition of text by means of types.Typesetting requires the prior process of designing a font and storing it in some manner...

. In the process, strips of lead metal were inserted to change the space between lines.

For webpage formatting, Cascading Style Sheets

Cascading Style Sheets

Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...

have a style parameter named "line-height" that sets the interline spacing for the currently selected font-size parameter.