Yes. The wildcard character (*) can be used match any number of characters except forward-slashes.
Examples:
*.comwill block all dot-com sites.*.somesite.comwill block all subdomains of somesite.com.*on its own will block all sites.
Note that * will also match no characters (e.g., foo*bar.com will block foobar.com).
If you want to match any number of characters including forward-slashes, use a double-wildcard (**).
If you want to match one or more characters, use a wildcard-plus (*+).