What does "leading" refer to in the context of typography?

Leading in typography specifically refers to the vertical space between lines of text. The term derives from the days of typesetting with metal type, where strips of lead were used to separate lines of type. Proper leading is crucial for readability; if the lines are too close together, the text can appear cramped, making it difficult for the reader’s eye to track. Conversely, too much space can disrupt the flow of reading. It is a key aspect of overall text layout and design, impacting both aesthetic quality and functional legibility.

The other options address different aspects of typography: the style of the font pertains to its design characteristics, such as serif vs. sans-serif; the height of the letters relates to the typeface's cap height or x-height rather than the space between lines; and the weight of the font describes how thick or thin the characters appear, which also does not involve the interval between lines. Understanding these distinctions further underscores the importance of leading in effective text presentation.