Using /wp-admin works, using /login gives a 404. Why?

I just did a manual install and tried to login, but was unable to do so using domain.com/login. I got a 404 error. When I used domain.com/wp-admin, no issues. Did I do something wrong or forget to do something?

/wp-admin/ is an existing directory, your server just adds the missing /.
/login is … nothing. The correct name is /wp-login.php.

If you have enabled permalinks it should work though.

To make /login always work add the following line to your .htaccess above the WordPress rules:

Redirect Permanent /login /wp-login.php

You can and should localize it if you use other languages:

# login in German
Redirect Permanent /anmelden /wp-login.php