Horizontal Spacing in LaTeX

LaTeX does spacing nicely most of the time. But, sometimes it becomes necessary to insert a little bit more of horizontal spacing. This might be between words of text, between math formulas or even between figures placed horizontally beside each other.

The following 3 TeX horizontal spacing macros can be used for this purpose:

1. \enskip: Inserts 0.5 em of horizontal space.

2. \quad: Inserts 1.0 em of horizontal space.

3. \qquad: Inserts 2.0 em of horizontal space.

Inside TeX, the above are defined as:

1. \def\enskip{\hskip.5em\relax}

2. \def\quad{\hskip1em\relax}

3. \def\qquad{\hskip2em\relax}

Note that em is a horizontal measurement unit and its value is dependent on the font being used. That is, it is a measurement unit that ships with a font. It is typically the width of the letter M of the font.

Reference: Pages 60 and 352 of The TeXBook by Donald E. Knuth