leading

The amount of vertical space between lines of text.

'Leading' comes from the metal-type era when typesetters inserted thin strips of lead (each one point thick) to increase the spacing between lines, for legibility or stylistic effects. Lines of normal text without leading are said to be set solid, and usually give a dense and dark appearance to the text block. Negative leading refers to less than normal spacing and is used to achieve dramatic visual impact in headlines, advertisements, posters, etc. In the desktop printing age, leading manipulation is achieved through pagemaking software such as Adobe PageMaker, Adobe InDesign, or Quark'Xpress.