What is another word for em space?
Pronunciation: [ɛm spˈe͡ɪs] (IPA) 
The em space, also known as the mutton space, is a typographical unit of measurement used in typography. It is named em space because it is the width of a capital letter "M" in a particular font. There are several synonyms used for the em space. One common synonym is the long dash, which is a horizontal line that is longer than a hyphen. Another synonym is the quad, which is a typographical term for a space that is the width of four lowercase letters "m." The em quad is a space that is the width of eight lowercase letters "m." In web design, the em space is often referred to as the "em" or "rem," which is a relative unit of measurement based on the font size.
