An en dash is a line that is a bit longer than a hyphen (-) but not as long as a regular dash. It is called an "en" dash because it is about the same width as the letter "n" in the alphabet.
When we use an en dash, it can do a few different things. One of the most common ways we use en dashes is to show a range between two numbers. For example, if you wanted to say that you were going to be on vacation from June 1st to June 7th, you could use an en dash in between those dates like this: "June 1–7."
We use en dashes in place of "to" or "through" when we want to connect two things in a range. So, instead of writing "June 1 to 7," we could use an en dash to make it shorter and clearer.
En dashes can also be used to show a relationship between two things. For example, if you were writing about a book that was written by two authors, you could use an en dash to show their collaboration. The book would be "by John Smith–Mary Williams," meaning that both John and Mary worked together to write it.
So, to sum up: an en dash is a line that is a bit longer than a hyphen and is used to show ranges between two things or to connect two things that have a relationship.