structure

Structure refers to the strokes making up the letter forms having the same weight throughout. It has two different categories: the first contains characters that has no to little weight change in the strokes of the letters such as sans serif and square serifs, the second containing characters with pronounced variation in the weight of the strokes such as roman, italic and script.
  Contrasting typefaces between both groups can create effect structural contrast. Its main use is to add contrast between headings and body text, to highlight an initial of a word or a name, or to emphasize a word in a line.