typography Typography is the art and technique of Typesetting, arranging type to make written language legibility, legible, readability, readable and beauty, appealing when displayed. The arrangement of type involves selecting typefaces, Point (typogra ...

, a quad (originally ''

quadrat A quadrat is a frame used in ecology, geography, and biology to isolate a standard unit of area for study of the distribution of an item over a large area. Quadrats typically occupy an area of 0.25 m2 and are traditionally square, but modern quad ...

'') was a metal spacer used in

letterpress Letterpress printing is a technique of relief printing for producing many copies by repeated direct impression of an inked, raised surface against individual sheets of paper or a continuous roll of paper. A worker composes and locks movable t ...

typesetting Typesetting is the composition of text for publication, display, or distribution by means of arranging physical ''type'' (or ''sort'') in mechanical systems or '' glyphs'' in digital systems representing '' characters'' (letters and other ...

. 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 Unicode or ''The Unicode Standard'' or TUS is a character encoding standard maintained by the Unicode Consortium designed to support the use of text in all of the world's writing systems that can be digitized. Version 16.0 defines 154,998 Char ...

character set as and , which are also defined to be canonically equivalent to and respectively.

LaTeX Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latices are found in nature, but synthetic latices are common as well. In nature, latex is found as a wikt:milky, milky fluid, which is present in 10% of all floweri ...

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

History

In 1683, in Joseph Moxon's book on the art of printing, the terms ''m'' and ''n quadrat'' are attested:

And as there is three Heighths or Sizes to be considered in Letters Cut to the same
Body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anim ...
, so is there three Sizes to be considered, with respect to the Thicknesses of all these Letters, when the ''Punches'' are to be Forged: For some are m thick; by m thick is meant m ''Quadrat'' thick, which is just so thick as the Body is high: Some are n thick; that is to say, n ''Quadrat'' thick, ' half so thick as the Body is high: And some are ''Space'' thick; that is, one quarter so thick as the Body is high; though ..we shall call these Spaces, Thick Spaces.

In 1771, in the first edition of the ''

Encyclopædia Britannica The is a general knowledge, general-knowledge English-language encyclopaedia. It has been published by Encyclopædia Britannica, Inc. since 1768, although the company has changed ownership seven times. The 2010 version of the 15th edition, ...

'', it says:

, in printing, a piece of metal cast like the letters, to fill up the void spaces between words, etc. There are quadrats of different sizes, as m-quadrats, n-quadrats, etc., which are, respectively, of the dimensions of these letters.

In 1841, in William Savage's ''A Dictionary of the Art of Printing'', the terms ''em'' and ''en quadrat'' are attested:

QUADRATS. Pieces of type metal, of the depth of the body of the respective sizes to which they are cast, and lower than types, so as to leave a blank space on the paper, when printed, where they are placed: an en quadrat is half as thick as its depth; an em quadrat is equal in thickness and depth, and, being square on its surface, is ''the'' true quadrat, from ''quadratus'', squared; a two em quadrat is twice the thickness of its depth; a three em three times; and a four em four times, as their names specify. Four ems are the largest quadrats that are cast. They are used to fill out short lines; to form white lines; and to justify letters, figures, &c., in any part of a line or page.

In 1903, in ''

Chambers Dictionary ''The Chambers Dictionary'' was first published by William and Robert Chambers as ''Chambers's English Dictionary'' in 1872. It was an expanded version of ''Chambers's Etymological Dictionary'' of 1867, compiled by James Donald. A second editio ...

'', the term ''quad'' is attested:

Quad, kwod, ' (') an abbreviation of ''quadrat''.— to fill with quadrats.
..br> Quadrat, kwod′rat, ' a piece of type-metal lower than the letters, used in spacing between words and filling out blank lines (commonly Quad)—distinguished as ''en'' , ''em'' , ''two-em'' , and ''three-em'' .

Notes

References

Typography Unicode Whitespace Printing {{typography-stub