typography Typography is the art and technique of arranging type to make written language legible, readable and appealing when displayed. The arrangement of type involves selecting typefaces, point sizes, line lengths, line-spacing ( leading), and ...

, a quad (originally ''

quadrat A quadrat is a frame, traditionally square, 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. Modern quadrats can for example be rectangular, circular, or irregul ...

'') was a metal spacer used in

letterpress Letterpress printing is a technique of relief printing. Using a printing press, the process allows many copies to be produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. A worker comp ...

typesetting Typesetting is the composition of text by means of arranging physical ''type'' (or ''sort'') in mechanical systems or ''glyphs'' in digital systems representing ''characters'' (letters and other symbols).Dictionary.com Unabridged. Random Ho ...

. 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, formally The Unicode Standard,The formal version reference is is an information technology Technical standard, standard for the consistent character encoding, encoding, representation, and handling of Character (computing), text expre ...

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.

History

In 1683, in

Joseph Moxon Joseph Moxon (8 August 1627 – February 1691), hydrographer to Charles II, was an English printer specialising in mathematical books and maps, a maker of globes and mathematical instruments, and mathematical lexicographer. He produced the ...

'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 anima ...
, 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 (Latin for "British Encyclopædia") is a general knowledge English-language encyclopaedia. It is published by Encyclopædia Britannica, Inc.; the company has existed since the 18th century, although it has changed ownership various time ...

'', 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 William Savage (1720 – 27 July 1789) was an English people, English composer, organist, and singer of the 18th century. He sang as a boy boy soprano, treble and alto, a countertenor, and as a bass (voice), bass. He is best remembered for his ...

'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'' (''TCD'') was first published by William Chambers (publisher), William and Robert Chambers (publisher born 1802), Robert Chambers as ''Chambers's English Dictionary'' in 1872. It was an expanded version of ''Chambers' ...

'', 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'' .

History

Notes

References

See also