Em space
Updated: 04/30/2020 by Computer Hope
An em space is a typographical space measuring one em in width.
Traditionally, for a font that uses the Latin alphabet, an em space is approximately the width of a capital letter M.
In modern digital typography, which attempts to standardize measurements for multiple languages and alphabets, an em space is usually smaller than a capital M.
In HTML
In HTML (hypertext markup language), to insert an em space, use the HTML entity  .
The size of a displayed em space may vary slightly according to the browser or device that renders the text.
Example
In the following sentence, word spacing is normal.
The quick brown fox jumped over the lazy dog.
In the following sentence, all spaces are em spaces.
The quick brown fox jumped over the lazy dog.