Leading

The vertical distance between successive

Baseline in a block of text, controlling how much white space separates lines of type. The term derives from the thin strips of lead (the metal) that compositors inserted between lines of

Movable Type to increase spacing. In digital typesetting, leading is typically expressed as a point value or as a ratio of font size (e.g., 1.5× or 150%). Appropriate leading is critical to

Readability: too tight and lines collide visually, particularly where

Descender and

Ascender are long; too loose and the eye struggles to track from the end of one line to the beginning of the next.