An en dash is a mid-sized dash (longer than a hyphen but shorter than an em dash) that is mostly used to show ranges in numbers and dates. It can also be used for clarity in forming complex compound adjectives. The en dash derives its name from the fact that it is meant to be the same width as the letter N.
Using an En Dash with Number and Date Ranges
A properly executed en dash is especially important in scientific and mathematical writing because it is used between numbers to represent the wordto.