Quad (typography)

Comparison of quad sorts in letterpress typesetting. In yellow is the cast metal sort name, and in black the corresponding Unicode whitespace character name.

In typography, a quad (originally quadrat[1]) was a metal spacer used in letterpress typesetting. The term was later adopted as the generic name for two common sizes of spaces in typography, regardless of the form of typesetting used. An em quad (originally m quadrat) is a space that is one em wide; as wide as the height of the font. An en quad (originally n quadrat) is a space that is one en wide: half the width of an em quad.

Both are encoded as characters in the General Punctuation code block of the Unicode character set as U+2000   EN QUAD and U+2001   EM QUAD, which are also defined to be canonically equivalent to U+2002   EN SPACE and U+2003   EM SPACE respectively.[2][3][4]

LaTeX markup uses \quad for an em quad, and has other related whitespace escape sequences.[5]

  1. ^ Sassoon, Rosemary (1993). Computers and Typography, v.1. Intellect. p. 40. ISBN 1871516234.
  2. ^ Jukka Korpela. "Unicode Spaces". Retrieved 2013-09-18.
  3. ^ Unicode Consortium. "The Unicode Standard, Version 6.2: General Punctuation, Range 2000–206F" (PDF). Retrieved 2013-09-18.
  4. ^ "Unicode Mail List Archive: RE: Difference between EM QUAD and EM SPACE". unicode.org. Retrieved 2021-06-05.
  5. ^ Spacing in math mode