Hyphen and minus are shorter and dashes are longer.
En-dashes and em-dashed are not included in the iso-8859-1 character set.
What does em and en mean?
En is half the width of em. Em is a typography measurement.
An em is a unit of measurement in the field of typography, equal to the currently specified point size.
http://en.wikipedia.org/wiki/Em_(typography)
keyboard Shortcut to en
alt + 0150 en-dash
keyboard Shortcut to em
alt + 151 em-dash
minus sign (the hyphen) is located on the keyboard
ISO-8859-1 Character set
http://htmlhelp.com/reference/charset/latin1.gif
Special Character Keyboard Shortcuts
http://tools.oratory.com/altcodes.htm